Dear ImGui - ImDrawList 1.93 Interactive Testbed

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The same ImDrawList calls, rendered by Dear ImGui 1.92.9 and by the 1.93 draw list rework, pixel by pixel. Every view runs the library's own code and a reference rasterizer that follows GPU rules. Hover a pixel to read its value. Zoom with the buttons or Ctrl + wheel (×1 is actual size), drag to pan. Examples are numbered, e.g. [107]: the numbers are stable and can be used in links and discussions.

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Interactive Testbed https://dearimgui.com/docs/drawlist_v193 <-- You are here
Discussion: Request for feedback: improved ImDrawList functions (now merged!) https://github.com/ocornut/imgui/issues/9504
Wiki: ImDrawList Vector Rendering Reference https://github.com/ocornut/imgui/wiki/Draw-List
Wiki: Pixel Perfect Anti-aliased Rendering https://github.com/ocornut/imgui/wiki/Pixel-Perfect-Rendering

1.92.9: The code as written, compiled against 1.92.9. Reference for the difference counts.
1.93 legacy: Same code on 1.93 inside PushDrawFlag(ImDrawFlags_StrokeLegacy, true), which is what io.ConfigDebugDrawListDefaultsToStrokeLegacy applies to every draw list. Each individual draw_list->AddXXX() call may specify ImDrawFlags_StrokeLegacy.
1.93 default: Same code on 1.93, nothing else changed. This is what you get after updating.
1.93 alternative: Another way to write the call in 1.93, where one is worth showing: a different function, an explicit stroke position, or code that reproduces the old look. Some examples have two (A and B), stacked.

View Pixel grid Input coordinates Triangles Mark differences

Colors

Style AntiAliasedLines AntiAliasedFill AntiAliasedLineEnds 1.93 Baked round corners 1.93 AntiAliasedLinesUseTex 1.92.9

Show ignoring differences up to / 255

Extra column 1.93 with AALineEnds JoinMiter CapSquare

Backend Who fills the triangles. Results only differ where an edge passes exactly through pixel centers.

Loading both library builds…

How pixels are produced

Each case runs inside a regular NewFrame() / Render() pair on the background draw list, with default style and font atlas.
The resulting triangles are rasterized in this page: pixel centers at +0.5, top-left fill rule as in Direct3D, vertices snapped to 1/256 pixel, bilinear texture filtering, standard alpha blending into an 8-bit target, no gamma correction.
The Backend option can hand the same triangles to your GPU through WebGL instead. The two can only disagree where a triangle edge passes exactly through pixel centers: Direct3D and OpenGL break that tie in opposite vertical directions, which moves such an edge by one pixel row.
Readout: rgb is the final color, a the accumulated opacity of everything drawn on that pixel.
GPU cross-check: pending.
Difference counts compare a view with the 1.92.9 view of the same case, on the largest per-channel difference of each pixel.