Expand description
Canvas provides an interface for drawing, and how the drawing is clipped and transformed.
Canvas contains a stack of Matrix and clip values.
Canvas and Paint together provide the state to draw into Surface or BaseDevice.
Each Canvas draw call transforms the geometry of the object by the concatenation of all
Matrix values in the stack. The transformed geometry is clipped by the intersection
of all of clip values in the stack. The Canvas draw calls use Paint to supply drawing
state such as color, Typeface, text size, stroke width, Shader and so on.
To draw to a pixel-based destination, create raster surface or GPU surface.
Request Canvas from Surface to obtain the interface to draw.
Canvas generated by raster surface draws to memory visible to the CPU.
Canvas generated by GPU surface uses Vulkan or OpenGL to draw to the GPU.
To draw to a document, obtain Canvas from SVG canvas, document PDF, or PictureRecorder.
Document based Canvas and other Canvas subclasses reference BaseDevice describing the
destination.
Canvas can be constructed to draw to Bitmap without first creating raster surface.
This approach may be deprecated in the future.