User-friendly methods to draw on an image
Contents
void DrawAnnotation( DrawContext context, const double x, const double y, const unsigned char *text );
DrawAnnotation() draws text on the image.
The format of the DrawAnnotation method is:
void DrawAnnotation( DrawContext context, const double x, const double y, const unsigned char *text );
drawing context
x ordinate to left of text
y ordinate to text baseline
text to draw
void DrawAffine( DrawContext context, const AffineMatrix *affine );
DrawAffine() adjusts the current affine transformation matrix with the specified affine transformation matrix. Note that the current affine transform is adjusted rather than replaced.
The format of the DrawAffine method is:
void DrawAffine( DrawContext context, const AffineMatrix *affine );
A description of each parameter follows:
Drawing context
Affine matrix parameters
DrawContext DrawAllocateContext( const DrawInfo *draw_info, Image *image );
DrawAllocateContext() allocates an initial drawing context which is an opaque handle required by the remaining drawing methods.
The format of the DrawAllocateContext method is:
DrawContext DrawAllocateContext( const DrawInfo *draw_info, Image *image );
Initial drawing defaults. Set to NULL to use GraphicsMagick defaults.
The image to draw on.
void DrawArc( DrawContext context, const double sx, const double sy, const double ex, const double ey, const double sd, const double ed );
DrawArc() draws an arc falling within a specified bounding rectangle on the image.
The format of the DrawArc method is:
void DrawArc( DrawContext context, const double sx, const double sy, const double ex, const double ey, const double sd, const double ed );
drawing context
starting x ordinate of bounding rectangle
starting y ordinate of bounding rectangle
ending x ordinate of bounding rectangle
ending y ordinate of bounding rectangle
starting degrees of rotation
ending degrees of rotation
void DrawBezier( DrawContext context, const unsigned long num_coords, const PointInfo *coordinates );
DrawBezier() draws a bezier curve through a set of points on the image.
The format of the DrawBezier method is:
void DrawBezier( DrawContext context, const unsigned long num_coords, const PointInfo *coordinates );
drawing context
number of coordinates
coordinates
void DrawCircle( DrawContext context, const double ox, const double oy, const double px, const double py );
DrawCircle() draws a circle on the image.
The format of the DrawCircle method is:
void DrawCircle( DrawContext context, const double ox, const double oy, const double px, const double py );
drawing context
origin x ordinate
origin y ordinate
perimeter x ordinate
perimeter y ordinate
char *DrawGetClipPath( DrawContext context );
DrawGetClipPath() obtains the current clipping path ID. The value returned must be deallocated by the user when it is no longer needed.
The format of the DrawGetClipPath method is:
char *DrawGetClipPath( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetClipPath( DrawContext context, const char *clip_path );
DrawSetClipPath() associates a named clipping path with the image. Only the areas drawn on by the clipping path will be modified as long as it remains in effect.
The format of the DrawSetClipPath method is:
void DrawSetClipPath( DrawContext context, const char *clip_path );
A description of each parameter follows:
drawing context
name of clipping path to associate with image
FillRule DrawGetClipRule( DrawContext context );
DrawGetClipRule() returns the current polygon fill rule to be used by the clipping path.
The format of the DrawGetClipRule method is:
FillRule DrawGetClipRule( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetClipRule( DrawContext context, const FillRule fill_rule );
DrawSetClipRule() set the polygon fill rule to be used by the clipping path.
The format of the DrawSetClipRule method is:
void DrawSetClipRule( DrawContext context, const FillRule fill_rule );
drawing context
fill rule (EvenOddRule or NonZeroRule)
ClipPathUnits DrawGetClipUnits( DrawContext context );
DrawGetClipUnits() returns the interpretation of clip path units.
The format of the DrawGetClipUnits method is:
ClipPathUnits DrawGetClipUnits( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetClipUnits( DrawContext context, const ClipPathUnits clip_units );
DrawSetClipUnits() sets the interpretation of clip path units.
The format of the DrawSetClipUnits method is:
void DrawSetClipUnits( DrawContext context, const ClipPathUnits clip_units );
drawing context
units to use (UserSpace, UserSpaceOnUse, or ObjectBoundingBox)
void DrawColor( DrawContext context, const double x, const double y, const PaintMethod paintMethod );
DrawColor() draws color on image using the current fill color, starting at specified position, and using specified paint method. The available paint methods are:
PointMethod: Recolors the target pixel ReplaceMethod: Recolor any pixel that matches the target pixel. FloodfillMethod: Recolors target pixels and matching neighbors. FillToBorderMethod: Recolor target pixels and neighbors not matching border color. ResetMethod: Recolor all pixels.
The format of the DrawColor method is:
void DrawColor( DrawContext context, const double x, const double y, const PaintMethod paintMethod );
drawing context
x ordinate
y ordinate
paint method
void DrawComment( DrawContext context, const char *comment );
DrawComment() adds a comment to a vector output stream.
The format of the DrawComment method is:
void DrawComment( DrawContext context, const char *comment );
A description of each parameter follows:
drawing context
comment text
void DrawDestroyContext( DrawContext context );
DrawDestroyContext() frees all resources associated with the drawing context. Once the drawing context has been freed, it should not be used any further unless it re-allocated.
The format of the DrawDestroyContext method is:
void DrawDestroyContext( DrawContext context );
A description of each parameter follows:
drawing context to destroy
void DrawEllipse( DrawContext context, const double ox, const double oy, const double rx, const double ry, const double start, const double end );
DrawEllipse() draws an ellipse on the image.
The format of the DrawEllipse method is:
void DrawEllipse( DrawContext context, const double ox, const double oy, const double rx, const double ry, const double start, const double end );
drawing context
origin x ordinate
origin y ordinate
radius in x
radius in y
starting rotation in degrees
ending rotation in degrees
PixelPacket DrawGetFillColor( DrawContext context );
DrawGetFillColor() returns the fill color used for drawing filled objects.
The format of the DrawGetFillColor method is:
PixelPacket DrawGetFillColor( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetFillColor( DrawContext context, const PixelPacket *fill_color );
DrawSetFillColor() sets the fill color to be used for drawing filled objects.
The format of the DrawSetFillColor method is:
void DrawSetFillColor( DrawContext context, const PixelPacket *fill_color );
drawing context
fill color
void DrawSetFillColorString( DrawContext context, const char *fill_color );
DrawSetFillColorString() sets the fill color to be used for drawing filled objects.
The format of the DrawSetFillColorString method is:
void DrawSetFillColorString( DrawContext context, const char *fill_color );
A description of each parameter follows:
drawing context
fill color
void DrawSetFillPatternURL( DrawContext context, const char *fill_url );
DrawSetFillPatternURL() sets the URL to use as a fill pattern for filling objects. Only local URLs ("#identifier") are supported at this time. These local URLs are normally created by defining a named fill pattern with DrawPushPattern/DrawPopPattern.
The format of the DrawSetFillPatternURL method is:
void DrawSetFillPatternURL( DrawContext context, const char *fill_url );
A description of each parameter follows:
drawing context
URL to use to obtain fill pattern.
double DrawGetFillOpacity( DrawContext context );
DrawGetFillOpacity() returns the opacity used when drawing using the fill color or fill texture. Fully opaque is 1.0.
The format of the DrawGetFillOpacity method is:
double DrawGetFillOpacity( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetFillOpacity( DrawContext context, const double fill_opacity );
DrawSetFillOpacity() sets the opacity to use when drawing using the fill color or fill texture. Fully opaque is 1.0.
The format of the DrawSetFillOpacity method is:
void DrawSetFillOpacity( DrawContext context, const double fill_opacity );
A description of each parameter follows:
drawing context
fill opacity
FillRule DrawGetFillRule( DrawContext context );
DrawGetFillRule() returns the fill rule used while drawing polygons.
The format of the DrawGetFillRule method is:
FillRule DrawGetFillRule( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetFillRule( DrawContext context, const FillRule fill_rule );
DrawSetFillRule() sets the fill rule to use while drawing polygons.
The format of the DrawSetFillRule method is:
void DrawSetFillRule( DrawContext context, const FillRule fill_rule );
A description of each parameter follows:
drawing context
fill rule (EvenOddRule or NonZeroRule)
char *DrawGetFont( DrawContext context );
DrawGetFont() returns a null-terminaged string specifying the font used when annotating with text. The value returned must be freed by the user when no longer needed.
The format of the DrawGetFont method is:
char *DrawGetFont( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetFont( DrawContext context, const char *font_name );
DrawSetFont() sets the fully-sepecified font to use when annotating with text.
The format of the DrawSetFont method is:
void DrawSetFont( DrawContext context, const char *font_name );
A description of each parameter follows:
drawing context
font name
char *DrawGetFontFamily( DrawContext context );
DrawGetFontFamily() returns the font family to use when annotating with text. The value returned must be freed by the user when it is no longer needed.
The format of the DrawGetFontFamily method is:
char *DrawGetFontFamily( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetFontFamily( DrawContext context, const char *font_family );
DrawSetFontFamily() sets the font family to use when annotating with text.
The format of the DrawSetFontFamily method is:
void DrawSetFontFamily( DrawContext context, const char *font_family );
A description of each parameter follows:
drawing context
font family
double DrawGetFontSize( DrawContext context );
DrawGetFontSize() returns the font pointsize used when annotating with text.
The format of the DrawGetFontSize method is:
double DrawGetFontSize( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetFontSize( DrawContext context, const double pointsize );
DrawSetFontSize() sets the font pointsize to use when annotating with text.
The format of the DrawSetFontSize method is:
void DrawSetFontSize( DrawContext context, const double pointsize );
A description of each parameter follows:
drawing context
text pointsize
StretchType DrawGetFontStretch( DrawContext context );
DrawGetFontStretch() returns the font stretch used when annotating with text.
The format of the DrawGetFontStretch method is:
StretchType DrawGetFontStretch( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetFontStretch( DrawContext context, const StretchType font_stretch );
DrawSetFontStretch() sets the font stretch to use when annotating with text. The AnyStretch enumeration acts as a wild-card "don't care" option.
The format of the DrawSetFontStretch method is:
void DrawSetFontStretch( DrawContext context, const StretchType font_stretch );
drawing context
font stretch (NormalStretch, UltraCondensedStretch, CondensedStretch, SemiCondensedStretch, SemiExpandedStretch, ExpandedStretch, ExtraExpandedStretch, UltraExpandedStretch, AnyStretch)
StyleType DrawGetFontStyle( DrawContext context );
DrawGetFontStyle() returns the font style used when annotating with text.
The format of the DrawGetFontStyle method is:
StyleType DrawGetFontStyle( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetFontStyle( DrawContext context, const StyleType style );
DrawSetFontStyle() sets the font style to use when annotating with text. The AnyStyle enumeration acts as a wild-card "don't care" option.
The format of the DrawSetFontStyle method is:
void DrawSetFontStyle( DrawContext context, const StyleType style );
A description of each parameter follows:
drawing context
font style (NormalStyle, ItalicStyle, ObliqueStyle, AnyStyle)
unsigned long DrawGetFontWeight( DrawContext context );
DrawGetFontWeight() returns the font weight used when annotating with text.
The format of the DrawGetFontWeight method is:
unsigned long DrawGetFontWeight( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetFontWeight( DrawContext context, const unsigned long font_weight );
DrawSetFontWeight() sets the font weight to use when annotating with text.
The format of the DrawSetFontWeight method is:
void DrawSetFontWeight( DrawContext context, const unsigned long font_weight );
drawing context
font weight (valid range 100-900)
GravityType DrawGetGravity( DrawContext context );
DrawGetGravity() returns the text placement gravity used when annotating with text.
The format of the DrawGetGravity method is:
GravityType DrawGetGravity( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetGravity( DrawContext context, const GravityType gravity );
DrawSetGravity() sets the text placement gravity to use when annotating with text.
The format of the DrawSetGravity method is:
void DrawSetGravity( DrawContext context, const GravityType gravity );
A description of each parameter follows:
drawing context
positioning gravity (NorthWestGravity, NorthGravity, NorthEastGravity, WestGravity, CenterGravity, EastGravity, SouthWestGravity, SouthGravity, SouthEastGravity)
void DrawComposite( DrawContext context, const CompositeOperator composite_operator, const double x, const double y, const double width, const double height, const Image *image );
DrawComposite() composites an image onto the current image, using the specified composition operator, specified position, and at the specified size.
The format of the DrawComposite method is:
void DrawComposite( DrawContext context, const CompositeOperator composite_operator, const double x, const double y, const double width, const double height, const Image *image );
drawing context
composition operator
x ordinate of top left corner
y ordinate of top left corner
Width to resize image to prior to compositing. Specify zero to use existing width.
Height to resize image to prior to compositing. Specify zero to use existing height.
Image to composite
void DrawLine( DrawContext context, const double sx, const double sy, const double ex, const double ey );
DrawLine() draws a line on the image using the current stroke color, stroke opacity, and stroke width.
The format of the DrawLine method is:
void DrawLine( DrawContext context, const double sx, const double sy, const double ex, const double ey );
drawing context
starting x ordinate
starting y ordinate
ending x ordinate
ending y ordinate
void DrawMatte( DrawContext context, const double x, const double y, const PaintMethod paint_method );
DrawMatte() paints on the image's opacity channel in order to set effected pixels to transparent. The available paint methods are:
PointMethod: Select the target pixel ReplaceMethod: Select any pixel that matches the target pixel. FloodfillMethod: Select the target pixel and matching neighbors. FillToBorderMethod: Select the target pixel and neighbors not matching border color. ResetMethod: Select all pixels.
The format of the DrawMatte method is:
void DrawMatte( DrawContext context, const double x, const double y, const PaintMethod paint_method );
drawing context
x ordinate
y ordinate
o paint_method:
void DrawPathClose( DrawContext context );
DrawPathClose() adds a path element to the current path which closes the current subpath by drawing a straight line from the current point to the current subpath's most recent starting point (usually, the most recent moveto point).
The format of the DrawPathClose method is:
void DrawPathClose( DrawContext context );
A description of each parameter follows:
drawing context
void DrawPathCurveToAbsolute( DrawContext context, const double x1, const double y1, const double x2, const double y2, const double x, const double y );
DrawPathCurveToAbsolute() draws a cubic Bezier curve from the current point to (x,y) using (x1,y1) as the control point at the beginning of the curve and (x2,y2) as the control point at the end of the curve using absolute coordinates. At the end of the command, the new current point becomes the final (x,y) coordinate pair used in the polybezier.
The format of the DrawPathCurveToAbsolute method is:
void DrawPathCurveToAbsolute( DrawContext context, const double x1, const double y1, const double x2, const double y2, const double x, const double y );
drawing context
x ordinate of control point for curve beginning
y ordinate of control point for curve beginning
x ordinate of control point for curve ending
y ordinate of control point for curve ending
x ordinate of the end of the curve
y ordinate of the end of the curve
void DrawPathCurveToRelative( DrawContext context, const double x1, const double y1, const double x2, const double y2, const double x, const double y );
DrawPathCurveToRelative() draws a cubic Bezier curve from the current point to (x,y) using (x1,y1) as the control point at the beginning of the curve and (x2,y2) as the control point at the end of the curve using relative coordinates. At the end of the command, the new current point becomes the final (x,y) coordinate pair used in the polybezier.
The format of the DrawPathCurveToRelative method is:
void DrawPathCurveToRelative( DrawContext context, const double x1, const double y1, const double x2, const double y2, const double x, const double y );
drawing context
x ordinate of control point for curve beginning
y ordinate of control point for curve beginning
x ordinate of control point for curve ending
y ordinate of control point for curve ending
x ordinate of the end of the curve
y ordinate of the end of the curve
void DrawPathCurveToQuadraticBezierAbsolute( DrawContext context, const double x1, const double y1, const double x, const double y );
DrawPathCurveToQuadraticBezierAbsolute() draws a quadratic Bezier curve from the current point to (x,y) using (x1,y1) as the control point using absolute coordinates. At the end of the command, the new current point becomes the final (x,y) coordinate pair used in the polybezier.
The format of the DrawPathCurveToQuadraticBezierAbsolute method is:
void DrawPathCurveToQuadraticBezierAbsolute( DrawContext context, const double x1, const double y1, const double x, const double y );
drawing context
x ordinate of the control point
y ordinate of the control point
x ordinate of final point
y ordinate of final point
void DrawPathCurveToQuadraticBezierRelative( DrawContext context, const double x1, const double y1, const double x, const double y );
DrawPathCurveToQuadraticBezierRelative() draws a quadratic Bezier curve from the current point to (x,y) using (x1,y1) as the control point using relative coordinates. At the end of the command, the new current point becomes the final (x,y) coordinate pair used in the polybezier.
The format of the DrawPathCurveToQuadraticBezierRelative method is:
void DrawPathCurveToQuadraticBezierRelative( DrawContext context, const double x1, const double y1, const double x, const double y );
drawing context
x ordinate of the control point
y ordinate of the control point
x ordinate of final point
y ordinate of final point
void DrawPathCurveToQuadraticBezierSmoothAbsolute( DrawContext context, const double x, const double y );
DrawPathCurveToQuadraticBezierSmoothAbsolute() draws a quadratic Bezier curve (using absolute coordinates) from the current point to (x,y). The control point is assumed to be the reflection of the control point on the previous command relative to the current point. (If there is no previous command or if the previous command was not a DrawPathCurveToQuadraticBezierAbsolute, DrawPathCurveToQuadraticBezierRelative, DrawPathCurveToQuadraticBezierSmoothAbsolut or DrawPathCurveToQuadraticBezierSmoothRelative, assume the control point is coincident with the current point.). At the end of the command, the new current point becomes the final (x,y) coordinate pair used in the polybezier.
The format of the DrawPathCurveToQuadraticBezierSmoothAbsolute method is:
void DrawPathCurveToQuadraticBezierSmoothAbsolute( DrawContext context, const double x, const double y );
drawing context
x ordinate of final point
y ordinate of final point
void DrawPathCurveToQuadraticBezierSmoothRelative( DrawContext context, const double x, const double y );
DrawPathCurveToQuadraticBezierSmoothAbsolute() draws a quadratic Bezier curve (using relative coordinates) from the current point to (x,y). The control point is assumed to be the reflection of the control point on the previous command relative to the current point. (If there is no previous command or if the previous command was not a DrawPathCurveToQuadraticBezierAbsolute, DrawPathCurveToQuadraticBezierRelative, DrawPathCurveToQuadraticBezierSmoothAbsolut or DrawPathCurveToQuadraticBezierSmoothRelative, assume the control point is coincident with the current point.). At the end of the command, the new current point becomes the final (x,y) coordinate pair used in the polybezier.
The format of the DrawPathCurveToQuadraticBezierSmoothRelative method is:
void DrawPathCurveToQuadraticBezierSmoothRelative( DrawContext context, const double x, const double y );
drawing context
x ordinate of final point
y ordinate of final point
void DrawPathCurveToSmoothAbsolute( DrawContext context, const double x2, const double y2, const double x, const double y );
DrawPathCurveToSmoothAbsolute() draws a cubic Bezier curve from the current point to (x,y) using absolute coordinates. The first control point is assumed to be the reflection of the second control point on the previous command relative to the current point. (If there is no previous command or if the previous command was not an DrawPathCurveToAbsolute, DrawPathCurveToRelative, DrawPathCurveToSmoothAbsolute or DrawPathCurveToSmoothRelative, assume the first control point is coincident with the current point.) (x2,y2) is the second control point (i.e., the control point at the end of the curve). At the end of the command, the new current point becomes the final (x,y) coordinate pair used in the polybezier.
The format of the DrawPathCurveToSmoothAbsolute method is:
void DrawPathCurveToSmoothAbsolute( DrawContext context, const double x2, const double y2, const double x, const double y );
drawing context
x ordinate of second control point
y ordinate of second control point
x ordinate of termination point
y ordinate of termination point
void DrawPathCurveToSmoothRelative( DrawContext context, const double x2, const double y2, const double x, const double y );
DrawPathCurveToSmoothRelative() draws a cubic Bezier curve from the current point to (x,y) using relative coordinates. The first control point is assumed to be the reflection of the second control point on the previous command relative to the current point. (If there is no previous command or if the previous command was not an DrawPathCurveToAbsolute, DrawPathCurveToRelative, DrawPathCurveToSmoothAbsolute or DrawPathCurveToSmoothRelative, assume the first control point is coincident with the current point.) (x2,y2) is the second control point (i.e., the control point at the end of the curve). At the end of the command, the new current point becomes the final (x,y) coordinate pair used in the polybezier.
The format of the DrawPathCurveToSmoothRelative method is:
void DrawPathCurveToSmoothRelative( DrawContext context, const double x2, const double y2, const double x, const double y );
drawing context
x ordinate of second control point
y ordinate of second control point
x ordinate of termination point
y ordinate of termination point
void DrawPathEllipticArcAbsolute( DrawContext context, const double rx, const double ry, const double x_axis_rotation, unsigned int large_arc_flag, unsigned int sweep_flag, const double x, const double y );
DrawPathEllipticArcAbsolute() draws an elliptical arc from the current point to (x, y) using absolute coordinates. The size and orientation of the ellipse are defined by two radii (rx, ry) and an xAxisRotation, which indicates how the ellipse as a whole is rotated relative to the current coordinate system. The center (cx, cy) of the ellipse is calculated automatically to satisfy the constraints imposed by the other parameters. largeArcFlag and sweepFlag contribute to the automatic calculations and help determine how the arc is drawn. If largeArcFlag is true then draw the larger of the available arcs. If sweepFlag is true, then draw the arc matching a clock-wise rotation.
The format of the DrawPathEllipticArcAbsolute method is:
void DrawPathEllipticArcAbsolute( DrawContext context, const double rx, const double ry, const double x_axis_rotation, unsigned int large_arc_flag, unsigned int sweep_flag, const double x, const double y );
drawing context
x radius
y radius
indicates how the ellipse as a whole is rotated relative to the current coordinate system
If non-zero (true) then draw the larger of the available arcs
If non-zero (true) then draw the arc matching a clock-wise rotation
void DrawPathEllipticArcRelative( DrawContext context, const double rx, const double ry, const double x_axis_rotation, unsigned int large_arc_flag, unsigned int sweep_flag, const double x, const double y );
DrawPathEllipticArcRelative() draws an elliptical arc from the current point to (x, y) using relative coordinates. The size and orientation of the ellipse are defined by two radii (rx, ry) and an xAxisRotation, which indicates how the ellipse as a whole is rotated relative to the current coordinate system. The center (cx, cy) of the ellipse is calculated automatically to satisfy the constraints imposed by the other parameters. largeArcFlag and sweepFlag contribute to the automatic calculations and help determine how the arc is drawn. If largeArcFlag is true then draw the larger of the available arcs. If sweepFlag is true, then draw the arc matching a clock-wise rotation.
The format of the DrawPathEllipticArcRelative method is:
void DrawPathEllipticArcRelative( DrawContext context, const double rx, const double ry, const double x_axis_rotation, unsigned int large_arc_flag, unsigned int sweep_flag, const double x, const double y );
drawing context
x radius
y radius
indicates how the ellipse as a whole is rotated relative to the current coordinate system
If non-zero (true) then draw the larger of the available arcs
If non-zero (true) then draw the arc matching a clock-wise rotation
void DrawPathFinish( DrawContext context );
DrawPathFinish() terminates the current path.
The format of the DrawPathFinish method is:
void DrawPathFinish( DrawContext context );
A description of each parameter follows:
drawing context
void DrawPathLineToAbsolute( DrawContext context, const double x, const double y );
DrawPathLineToAbsolute() draws a line path from the current point to the given coordinate using absolute coordinates. The coordinate then becomes the new current point.
The format of the DrawPathLineToAbsolute method is:
void DrawPathLineToAbsolute( DrawContext context, const double x, const double y );
drawing context
target x ordinate
target y ordinate
void DrawPathLineToRelative( DrawContext context, const double x, const double y );
DrawPathLineToRelative() draws a line path from the current point to the given coordinate using relative coordinates. The coordinate then becomes the new current point.
The format of the DrawPathLineToRelative method is:
void DrawPathLineToRelative( DrawContext context, const double x, const double y );
drawing context
target x ordinate
target y ordinate
void DrawPathLineToHorizontalAbsolute( DrawContext context, const double x );
DrawPathLineToHorizontalAbsolute() draws a horizontal line path from the current point to the target point using absolute coordinates. The target point then becomes the new current point.
The format of the DrawPathLineToHorizontalAbsolute method is:
void DrawPathLineToHorizontalAbsolute( DrawContext context, const double x );
drawing context
target x ordinate
void DrawPathLineToHorizontalRelative( DrawContext context, const double x );
DrawPathLineToHorizontalRelative() draws a horizontal line path from the current point to the target point using relative coordinates. The target point then becomes the new current point.
The format of the DrawPathLineToHorizontalRelative method is:
void DrawPathLineToHorizontalRelative( DrawContext context, const double x );
A description of each parameter follows:
drawing context
target x ordinate
void DrawPathLineToVerticalAbsolute( DrawContext context, const double y );
DrawPathLineToVerticalAbsolute() draws a vertical line path from the current point to the target point using absolute coordinates. The target point then becomes the new current point.
The format of the DrawPathLineToVerticalAbsolute method is:
void DrawPathLineToVerticalAbsolute( DrawContext context, const double y );
drawing context
target y ordinate
void DrawPathLineToVerticalRelative( DrawContext context, const double y );
DrawPathLineToVerticalRelative() draws a vertical line path from the current point to the target point using relative coordinates. The target point then becomes the new current point.
The format of the DrawPathLineToVerticalRelative method is:
void DrawPathLineToVerticalRelative( DrawContext context, const double y );
drawing context
target y ordinate
void DrawPathMoveToAbsolute( DrawContext context, const double x, const double y );
DrawPathMoveToAbsolute() starts a new sub-path at the given coordinate using absolute coordinates. The current point then becomes the specified coordinate.
The format of the DrawPathMoveToAbsolute method is:
void DrawPathMoveToAbsolute( DrawContext context, const double x, const double y );
drawing context
target x ordinate
target y ordinate
void DrawPathMoveToRelative( DrawContext context, const double x, const double y );
DrawPathMoveToRelative() starts a new sub-path at the given coordinate using relative coordinates. The current point then becomes the specified coordinate.
The format of the DrawPathMoveToRelative method is:
void DrawPathMoveToRelative( DrawContext context, const double x, const double y );
drawing context
target x ordinate
target y ordinate
void DrawPathStart( DrawContext context );
DrawPathStart() declares the start of a path drawing list which is terminated by a matching DrawPathFinish() command. All other DrawPath commands must be enclosed between a DrawPathStart() and a DrawPathFinish() command. This is because path drawing commands are subordinate commands and they do not function by themselves.
The format of the DrawPathStart method is:
void DrawPathStart( DrawContext context );
A description of each parameter follows:
drawing context
DrawInfo *DrawPeekGraphicContext( const DrawContext context );
DrawPeekGraphicContext() returns a copy of the the DrawInfo structure at the head of the drawing context stack. The user is responsible for deallocating the returned object using DestroyDrawInfo.
The format of the DrawPeekGraphicContext method is:
DrawInfo *DrawPeekGraphicContext( const DrawContext context );
A description of each parameter follows:
drawing context
void DrawPoint( DrawContext context, const double x, const double y );
DrawPoint() draws a point using the current stroke color and stroke thickness at the specified coordinates.
The format of the DrawPoint method is:
void DrawPoint( DrawContext context, const double x, const double y );
A description of each parameter follows:
drawing context
target x coordinate
target y coordinate
void DrawPolygon( DrawContext context, const unsigned long num_coords, const PointInfo *coordinates );
DrawPolygon() draws a polygon using the current stroke, stroke width, and fill color or texture, using the specified array of coordinates.
The format of the DrawPolygon method is:
void DrawPolygon( DrawContext context, const unsigned long num_coords, const PointInfo *coordinates );
drawing context
number of coordinates
coordinate array
void DrawPolyline( DrawContext context, const unsigned long num_coords, const PointInfo *coordinates );
DrawPolyline() draws a polyline using the current stroke, stroke width, and fill color or texture, using the specified array of coordinates.
The format of the DrawPolyline method is:
void DrawPolyline( DrawContext context, const unsigned long num_coords, const PointInfo *coordinates );
drawing context
number of coordinates
coordinate array
void DrawPopClipPath( DrawContext context );
DrawPopClipPath() terminates a clip path definition.
The format of the DrawPopClipPath method is:
void DrawPopClipPath( DrawContext context );
A description of each parameter follows:
drawing context
void DrawPopDefs( DrawContext context );
DrawPopDefs() terminates a definition list
The format of the DrawPopDefs method is:
void DrawPopDefs( DrawContext context );
A description of each parameter follows:
drawing context
void DrawPopGraphicContext( DrawContext context );
DrawPopGraphicContext() destroys the current context returning to the previously pushed context. Multiple contexts may exist. It is an error to attempt to pop more contexts than have been pushed, and it is proper form to pop all contexts which have been pushed.
The format of the DrawPopGraphicContext method is:
void DrawPopGraphicContext( DrawContext context );
A description of each parameter follows:
drawing context
void DrawPopPattern( DrawContext context );
DrawPopPattern() terminates a pattern definition.
The format of the DrawPopPattern method is:
void DrawPopPattern( DrawContext context );
A description of each parameter follows:
drawing context
void DrawPushClipPath( DrawContext context, const char *clip_path_id );
DrawPushClipPath() starts a clip path definition which is comprized of any number of drawing commands and terminated by a DrawPopClipPath() command.
The format of the DrawPushClipPath method is:
void DrawPushClipPath( DrawContext context, const char *clip_path_id );
A description of each parameter follows:
drawing context
string identifier to associate with the clip path for later use.
void DrawPushDefs( DrawContext context );
DrawPushDefs() indicates that commands up to a terminating DrawPopDefs() command create named elements (e.g. clip-paths, textures, etc.) which may safely be processed earlier for the sake of efficiency.
The format of the DrawPushDefs method is:
void DrawPushDefs( DrawContext context );
A description of each parameter follows:
drawing context
void DrawPushGraphicContext( DrawContext context );
DrawPushGraphicContext() clones the current drawing context to create a new drawing context. The original drawing context(s) may be returned to by invoking DrawPopGraphicContext(). The contexts are stored on a context stack. For every Pop there must have already been an equivalent Push.
The format of the DrawPushGraphicContext method is:
void DrawPushGraphicContext( DrawContext context );
A description of each parameter follows:
drawing context
void DrawPushPattern( DrawContext context, const char *pattern_id, const double x, const double y, const double width, const double height );
DrawPushPattern() indicates that subsequent commands up to a DrawPopPattern() command comprise the definition of a named pattern. The pattern space is assigned top left corner coordinates, a width and height, and becomes its own drawing space. Anything which can be drawn may be used in a pattern definition. Named patterns may be used as stroke or brush definitions.
The format of the DrawPushPattern method is:
void DrawPushPattern( DrawContext context, const char *pattern_id, const double x, const double y, const double width, const double height );
drawing context
pattern identification for later reference
x ordinate of top left corner
y ordinate of top left corner
width of pattern space
height of pattern space
void DrawRectangle( DrawContext context, const double x1, const double y1, const double x2, const double y2 );
DrawRectangle() draws a rectangle given two coordinates and using the current stroke, stroke width, and fill settings.
The format of the DrawRectangle method is:
void DrawRectangle( DrawContext context, const double x1, const double y1, const double x2, const double y2 );
x ordinate of first coordinate
y ordinate of first coordinate
x ordinate of second coordinate
y ordinate of second coordinate
int DrawRender( const DrawContext context );
DrawRender() renders all preceding drawing commands onto the image.
The format of the DrawRender method is:
int DrawRender( const DrawContext context );
A description of each parameter follows:
drawing context
void DrawRotate( DrawContext context, const double degrees );
DrawRotate() applies the specified rotation to the current coordinate space.
The format of the DrawRotate method is:
void DrawRotate( DrawContext context, const double degrees );
A description of each parameter follows:
drawing context
degrees of rotation
void DrawRoundRectangle( DrawContext context, double x1, double y1, double x2, double y2, double rx, double ry );
DrawRoundRectangle() draws a rounted rectangle given two coordinates, x & y corner radiuses and using the current stroke, stroke width, and fill settings.
The format of the DrawRoundRectangle method is:
void DrawRoundRectangle( DrawContext context, double x1, double y1, double x2, double y2, double rx, double ry );
drawing context
x ordinate of first coordinate
y ordinate of first coordinate
x ordinate of second coordinate
y ordinate of second coordinate
radius of corner in horizontal direction
radius of corner in vertical direction
void DrawScale( DrawContext context, const double x, const double y );
DrawScale() adjusts the scaling factor to apply in the horizontal and vertical directions to the current coordinate space.
The format of the DrawScale method is:
void DrawScale( DrawContext context, const double x, const double y );
A description of each parameter follows:
drawing context
horizontal scale factor
vertical scale factor
void DrawSkewX( DrawContext context, const double degrees );
DrawSkewX() skews the current coordinate system in the horizontal direction.
The format of the DrawSkewX method is:
void DrawSkewX( DrawContext context, const double degrees );
A description of each parameter follows:
drawing context
number of degrees to skew the coordinates
void DrawSkewY( DrawContext context, const double degrees );
DrawSkewY() skews the current coordinate system in the vertical direction.
The format of the DrawSkewY method is:
void DrawSkewY( DrawContext context, const double degrees );
A description of each parameter follows:
drawing context
number of degrees to skew the coordinates
void DrawSetStopColor( DrawContext context, const PixelPacket *stop_color, const double offset );
DrawSetStopColor() sets the stop color and offset for gradients
The format of the DrawSetStopColor method is:
void DrawSetStopColor( DrawContext context, const PixelPacket *stop_color, const double offset );
drawing context
o stop_color:
o offset:
PixelPacket DrawGetStrokeColor( DrawContext context );
DrawGetStrokeColor() returns the color used for stroking object outlines.
The format of the DrawGetStrokeColor method is:
PixelPacket DrawGetStrokeColor( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetStrokeColor( DrawContext context, const PixelPacket *stroke_color );
DrawSetStrokeColor() sets the color used for stroking object outlines.
The format of the DrawSetStrokeColor method is:
void DrawSetStrokeColor( DrawContext context, const PixelPacket *stroke_color );
drawing context
stroke color
void DrawSetStrokeColorString( DrawContext context, const char *stroke_color );
DrawSetStrokeColorString() sets the color used for stroking object outlines.
The format of the DrawSetStrokeColorString method is:
void DrawSetStrokeColorString( DrawContext context, const char *stroke_color );
drawing context
stroke color
void DrawSetStrokePatternURL( DrawContext context, const char *stroke_url );
DrawSetStrokePatternURL() sets the pattern used for stroking object outlines.
The format of the DrawSetStrokePatternURL method is:
void DrawSetStrokePatternURL( DrawContext context, const char *stroke_url );
A description of each parameter follows:
drawing context
URL specifying pattern ID (e.g. "#pattern_id")
unsigned int DrawGetStrokeAntialias( DrawContext context );
DrawGetStrokeAntialias() returns the current stroke antialias setting. Stroked outlines are antialiased by default. When antialiasing is disabled stroked pixels are thresholded to determine if the stroke color or underlying canvas color should be used.
The format of the DrawGetStrokeAntialias method is:
unsigned int DrawGetStrokeAntialias( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetStrokeAntialias( DrawContext context, const unsigned int stroke_antialias );
DrawSetStrokeAntialias() controls whether stroked outlines are antialiased. Stroked outlines are antialiased by default. When antialiasing is disabled stroked pixels are thresholded to determine if the stroke color or underlying canvas color should be used.
The format of the DrawSetStrokeAntialias method is:
void DrawSetStrokeAntialias( DrawContext context, const unsigned int stroke_antialias );
drawing context
set to false (zero) to disable antialiasing
double *DrawGetStrokeDashArray( DrawContext context, unsigned long *num_elems );
DrawGetStrokeDashArray() returns an array representing the pattern of dashes and gaps used to stroke paths (see DrawSetStrokeDashArray). The array must be freed once it is no longer required by the user.
The format of the DrawGetStrokeDashArray method is:
double *DrawGetStrokeDashArray( DrawContext context, unsigned long *num_elems );
A description of each parameter follows:
drawing context
address to place number of elements in dash array
void DrawSetStrokeDashArray( DrawContext context, const unsigned long num_elems, const double *dasharray );
DrawSetStrokeDashArray() specifies the pattern of dashes and gaps used to stroke paths. The strokeDashArray represents an array of numbers that specify the lengths of alternating dashes and gaps in pixels. If an odd number of values is provided, then the list of values is repeated to yield an even number of values. To remove an existing dash array, pass a zero num_elems argument and null dasharray. A typical stroke dash array might contain the members 5 3 2.
The format of the DrawSetStrokeDashArray method is:
void DrawSetStrokeDashArray( DrawContext context, const unsigned long num_elems, const double *dasharray );
drawing context
number of elements in dash array
dash array values
double DrawGetStrokeDashOffset( DrawContext context );
DrawGetStrokeDashOffset() returns the offset into the dash pattern to start the dash.
The format of the DrawGetStrokeDashOffset method is:
double DrawGetStrokeDashOffset( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetStrokeDashOffset( DrawContext context, const double dash_offset );
DrawSetStrokeDashOffset() specifies the offset into the dash pattern to start the dash.
The format of the DrawSetStrokeDashOffset method is:
void DrawSetStrokeDashOffset( DrawContext context, const double dash_offset );
drawing context
dash offset
LineCap DrawGetStrokeLineCap( DrawContext context );
DrawGetStrokeLineCap() returns the shape to be used at the end of open subpaths when they are stroked. Values of LineCap are UndefinedCap, ButtCap, RoundCap, and SquareCap.
The format of the DrawGetStrokeLineCap method is:
LineCap DrawGetStrokeLineCap( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetStrokeLineCap( DrawContext context, const LineCap linecap );
DrawSetStrokeLineCap() specifies the shape to be used at the end of open subpaths when they are stroked. Values of LineCap are UndefinedCap, ButtCap, RoundCap, and SquareCap.
The format of the DrawSetStrokeLineCap method is:
void DrawSetStrokeLineCap( DrawContext context, const LineCap linecap );
drawing context
linecap style
LineJoin DrawGetStrokeLineJoin( DrawContext context );
DrawGetStrokeLineJoin() returns the shape to be used at the corners of paths (or other vector shapes) when they are stroked. Values of LineJoin are UndefinedJoin, MiterJoin, RoundJoin, and BevelJoin.
The format of the DrawGetStrokeLineJoin method is:
LineJoin DrawGetStrokeLineJoin( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetStrokeLineJoin( DrawContext context, const LineJoin linejoin );
DrawSetStrokeLineJoin() specifies the shape to be used at the corners of paths (or other vector shapes) when they are stroked. Values of LineJoin are UndefinedJoin, MiterJoin, RoundJoin, and BevelJoin.
The format of the DrawSetStrokeLineJoin method is:
void DrawSetStrokeLineJoin( DrawContext context, const LineJoin linejoin );
A description of each parameter follows:
drawing context
line join style
unsigned long DrawGetStrokeMiterLimit( DrawContext context );
DrawGetStrokeMiterLimit() returns the miter limit. When two line segments meet at a sharp angle and miter joins have been specified for 'lineJoin', it is possible for the miter to extend far beyond the thickness of the line stroking the path. The miterLimit' imposes a limit on the ratio of the miter length to the 'lineWidth'.
The format of the DrawGetStrokeMiterLimit method is:
unsigned long DrawGetStrokeMiterLimit( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetStrokeMiterLimit( DrawContext context, const unsigned long miterlimit );
DrawSetStrokeMiterLimit() specifies the miter limit. When two line segments meet at a sharp angle and miter joins have been specified for 'lineJoin', it is possible for the miter to extend far beyond the thickness of the line stroking the path. The miterLimit' imposes a limit on the ratio of the miter length to the 'lineWidth'.
The format of the DrawSetStrokeMiterLimit method is:
void DrawSetStrokeMiterLimit( DrawContext context, const unsigned long miterlimit );
drawing context
miter limit
double DrawGetStrokeOpacity( DrawContext context );
DrawGetStrokeOpacity() returns the opacity of stroked object outlines.
The format of the DrawGetStrokeOpacity method is:
double DrawGetStrokeOpacity( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetStrokeOpacity( DrawContext context, const double stroke_opacity );
DrawSetStrokeOpacity() specifies the opacity of stroked object outlines.
The format of the DrawSetStrokeOpacity method is:
void DrawSetStrokeOpacity( DrawContext context, const double stroke_opacity );
drawing context
stroke opacity. The value 1.0 is opaque.
double DrawGetStrokeWidth( DrawContext context );
DrawGetStrokeWidth() returns the width of the stroke used to draw object outlines.
The format of the DrawGetStrokeWidth method is:
double DrawGetStrokeWidth( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetStrokeWidth( DrawContext context, const double stroke_width );
DrawSetStrokeWidth() sets the width of the stroke used to draw object outlines.
The format of the DrawSetStrokeWidth method is:
void DrawSetStrokeWidth( DrawContext context, const double stroke_width );
A description of each parameter follows:
drawing context
stroke width
unsigned int DrawGetTextAntialias( DrawContext context );
DrawGetTextAntialias() returns the current text antialias setting, which determines whether text is antialiased. Text is antialiased by default.
The format of the DrawGetTextAntialias method is:
unsigned int DrawGetTextAntialias( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetTextAntialias( DrawContext context, const unsigned int text_antialias );
DrawSetTextAntialias() controls whether text is antialiased. Text is antialiased by default.
The format of the DrawSetTextAntialias method is:
void DrawSetTextAntialias( DrawContext context, const unsigned int text_antialias );
drawing context
antialias boolean. Set to false (0) to disable antialiasing.
DecorationType DrawGetTextDecoration( DrawContext context );
DrawGetTextDecoration() returns the decoration applied when annotating with text.
The format of the DrawGetTextDecoration method is:
DecorationType DrawGetTextDecoration( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetTextDecoration( DrawContext context, const DecorationType decoration );
DrawSetTextDecoration() specifies a decoration to be applied when annotating with text.
The format of the DrawSetTextDecoration method is:
void DrawSetTextDecoration( DrawContext context, const DecorationType decoration );
drawing context
text decoration. One of NoDecoration, UnderlineDecoration, OverlineDecoration, or LineThroughDecoration
char *DrawGetTextEncoding( DrawContext context );
DrawGetTextEncoding() returns a null-terminated string which specifies the code set used for text annotations. The string must be freed by the user once it is no longer required.
The format of the DrawGetTextEncoding method is:
char *DrawGetTextEncoding( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetTextEncoding( DrawContext context, const char *encoding );
DrawSetTextEncoding() specifies specifies the code set to use for text annotations. The only character encoding which may be specified at this time is "UTF-8" for representing Unicode as a sequence of bytes. Specify an empty string to set text encoding to the system's default. Successful text annotation using Unicode may require fonts designed to support Unicode.
The format of the DrawSetTextEncoding method is:
void DrawSetTextEncoding( DrawContext context, const char *encoding );
A description of each parameter follows:
drawing context
character string specifying text encoding
PixelPacket DrawGetTextUnderColor( DrawContext context );
DrawGetTextUnderColor() returns the color of a background rectangle to place under text annotations.
The format of the DrawGetTextUnderColor method is:
PixelPacket DrawGetTextUnderColor( DrawContext context );
A description of each parameter follows:
drawing context
void DrawSetTextUnderColor( DrawContext context, const PixelPacket *under_color );
DrawSetTextUnderColor() specifies the color of a background rectangle to place under text annotations.
The format of the DrawSetTextUnderColor method is:
void DrawSetTextUnderColor( DrawContext context, const PixelPacket *under_color );
drawing context
text under color
void DrawSetTextUnderColorString( DrawContext context, const char *under_color );
DrawSetTextUnderColorString() specifies the color of a background rectangle to place under text annotations.
The format of the DrawSetTextUnderColorString method is:
void DrawSetTextUnderColorString( DrawContext context, const char *under_color );
drawing context
text under color
void DrawTranslate( DrawContext context, const double x, const double y );
DrawTranslate() applies a translation to the current coordinate system which moves the coordinate system origin to the specified coordinate.
The format of the DrawTranslate method is:
void DrawTranslate( DrawContext context, const double x, const double y );
drawing context
new x ordinate for coordinate system origin
new y ordinate for coordinate system origin
void DrawSetViewbox( DrawContext context, unsigned long x1, unsigned long y1, unsigned long x2, unsigned long y2 );
DrawSetViewbox() sets the overall canvas size to be recorded with the drawing vector data. Usually this will be specified using the same size as the canvas image. When the vector data is saved to SVG or MVG formats, the viewbox is use to specify the size of the canvas image that a viewer will render the vector data on.
The format of the DrawSetViewbox method is:
void DrawSetViewbox( DrawContext context, unsigned long x1, unsigned long y1, unsigned long x2, unsigned long y2 );
drawing context
left x ordinate
top y ordinate
right x ordinate
bottom y ordinate
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