ImageMagick DrawInfo Structure

The DrawInfo structure is used to support annotating an image using drawing commands.
 
Methods Supporting DrawInfo
Method
Description
GetDrawInfo() Allocate new structure with defaults set.
CloneDrawInfo() Copy existing structure, allocating new structure in the process.
DestroyDrawInfo() Deallocate structure, including any members.
DrawImage() Render primitives to image.

The members of the DrawInfo structure are shown in the following table. The structure is initialized to reasonable defaults by first initializing the equivalent members of ImageInfo, and then initializing the entire structure using GetDrawInfo().
 
DrawInfo Structure Members Supporting DrawImage()
Member
Type
Description
affine AffineInfo Coordinate transformation (rotation, scaling, and translation).
border_color PixelPacket Border color
box PixelPacket Text solid background color.
decorate DecorationType Text decoration type.
density char * Text rendering density in DPI (effects scaling font according to pointsize). E.g. "72x72"
fill PixelPacket Object internal fill (within outline) color.
font char * Font to use when rendering text.
gravity GravityType Text placement preference (e.g. NorthWestGravity).
linewidth double Stroke (outline) drawing width in pixels.
pointsize double Font size (also see density).
primitive char * Space or new-line delimited list of text drawing primitives (e.g "text 100,100 Cockatoo"). See the table Drawing Primitives for the available drawing primitives.
stroke PixelPacket Object stroke (outline) color.
stroke_antialias unsigned int Set to True (non-zero) to obtain anti-aliased stroke rendering.
text_antialias unsigned int Set to True (non-zero) to obtain anti-aliased text rendering.
tile Image * Image texture to draw with. Use an image containing a single color (e.g. a 1x1 image) to draw in a solid color.

Drawing Primitives

The drawing primitives shown in the following table may be supplied as a space or new-line deliminted list to the primitive member. Primitives which set drawing options effect the results from subsequent drawing operations. See the 'push graphic-context' and 'pop graphic-context'  primitives for a way to control the propogation of drawing options.
 
Drawing Primitives
Primitive
Arguments
Purpose
affine sx,rx,ry,sy,tx,ty Apply coordinate transformations to support scaling (s), rotation (r), and translation (t). Angles are specified in radians. Equivalent to SVG matrix command which supplies a transformation matrix.
angle angle Specify object drawing angle.
arc startX,startY endX,endY startDegrees,endDegrees Draw an arc.
bezier x1,y1, x2,y2, x3,y3, ..., xN,yN Draw a bezier curve.
circle originX,originY perimX,perimY Draw a circle.
color x,y (point|replace|floodfill|filltoborder|reset) Set color in image according to specified colorization rule.
decorate (none|underline|overline|line-through) Specify text decoration.
ellipse originX,originY width,height arcStart,arcEnd Draw an ellipse.
fill colorspec Specifiy object filling color.
fill-opacity opacity Specify object fill opacity.
font fontname Specify text drawing font.
gravity (NorthWest|North|NorthEast|West|Center|East|SouthWest|South|SouthEast) Specify text positioning gravity.
image x,y width,height filename Composite image at position, scaled to specified width and height, and specified filename. If width or height is zero, scaling is not performed.
line startX,startY endX,endY Draw a line.
matte x,y (point|replace|floodfill|filltoborder|reset) Set matte in image according to specified colorization rule.
opacity fillOpacity strokeOpacity Specify drawing fill and stroke opacities.
path 'SVG-compatible path arguments' Draw using SVG-compatible path drawing commands.
point x,y Set point to fill color.
pointsize pointsize Specify text drawing pointsize (scaled to density).
polygon x1,y1, x2,y2, x3,y3, ..., xN,yN Draw a polygon.
polyline x1,y1, x2,y2, x3,y3, ..., xN,yN Draw a polyline.
pop graphic-context Remove options set since previous "push graphic-context" command. Options revert to those in effect prior to pushing the graphic context.
push graphic-context Specify new graphic context.
rect upperLeftX,upperLeftY lowerRightX,lowerRightY Draw a rectangle.
rotate angle Specify coordiante space rotation. Subsequent objects are drawn with coordate space rotated by specified angle. 
roundrectangle centerX,centerY width,hight cornerWidth,cornerHeight Draw a rectangle with rounded corners.
stroke colorspec Specify object stroke (outline) color.
stroke-antialias stroke_antialias (0 or 1) Specify if stroke should be antialiased or not.
stroke-dash value Specify pattern to be used when drawing stroke.
stroke-opacity opacity Specify opacity of stroke drawing color.
stroke-width linewidth Specify stroke (outline) width in pixels.
text x,y "some text" Draw text at position.
text-antialias text_antialias (0 or 1) Specify if rendered text is to be antialiased (blend edges).
scale x,y Specify scaling to be applied to coordintate space for subsequent drawing commands.
translate x,y Specify center of coordinate space to use for subsequent drawing commands.

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