Implements a simple drawing api

Windows

Open git bash to the directory containing this repository.

canvas-drawer $ mkdir build
canvas-drawer $ cd build
canvas-drawer/build $ cmake -G "Visual Studio 16 2019" ..
canvas-drawer/build $ start Draw-2D.sln

Your solution file should contain two projects: pixmap_art and pixmap_test. To run from the git bash command shell,

canvas-drawer/build $ ../bin/Debug/draw_test
canvas-drawer/build $ ../bin/Debug/draw_art

macOS

Open terminal to the directory containing this repository.

canvas-drawer $ mkdir build
canvas-drawer $ cd build
canvas-drawer/build $ cmake ..
canvas-drawer/build $ make

To run each program from build, you would type

canvas-drawer/build $ ../bin/draw_test
canvas-drawer/build $ ../bin/draw_art

• LINES
  • Interpolation between two vertices with individual stroke color/alpha/width attributes
• TRIANGLES
  • Joins three vertices into three lines with per-vertex fill color and alpha
• QUADS
  • Joins four vertices into two triangles
• FANS
  • Joins $n$ vertices into a polygon made of $n-1$ triangles. First vertex specifies the central vertex where all triangles meet.

• Quads
• Triangle Fans
• Add and subtract blend modes
• Alpha blending

Background color gradient uses a triangle fan to specify colors at specific points and is blended over the triangles using alpha blending. Rectangles are implemented with a QUAD primitive and use the subtract blend mode. The central sphere is a triangle fan with per-vertex shading.