Backends: WebGPU: fixed passing non-integer sizes to wgpuRenderPassEncoderSetViewport(). (#9515, #8628)

backends/imgui_impl_wgpu.cpp

diff --git a/backends/imgui_impl_wgpu.cpp b/backends/imgui_impl_wgpu.cpp
index ce5974b..43a7fbb 100644
--- a/backends/imgui_impl_wgpu.cpp
+++ b/backends/imgui_impl_wgpu.cpp
@@ -20,6 +20,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2026-08-18: Fixed passing non-integer sizes to `wgpuRenderPassEncoderSetViewport() when FramebufferScale is >1.0f. (#9515, #8628)
 //  2026-04-23: Added support for standard draw callbacks (in platform_io): DrawCallback_ResetRenderState, DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest. (#9378)
 //  2026-03-25: Added support for WGVK native backend via IMGUI_IMPL_WEBGPU_BACKEND_WGVK define, with SPIRV shaders if WGSL is not available. (#9316, #9246, #9257)
 //  2026-03-09: Removed support for Emscripten < 4.0.10. (#9281)
@@ -440,7 +441,9 @@
     }
 
     // Setup viewport
-    wgpuRenderPassEncoderSetViewport(ctx, 0, 0, draw_data->FramebufferScale.x * draw_data->DisplaySize.x, draw_data->FramebufferScale.y * draw_data->DisplaySize.y, 0, 1);
+    int fb_width = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
+    int fb_height = (int)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
+    wgpuRenderPassEncoderSetViewport(ctx, 0, 0, fb_width, fb_height, 0, 1);
 
     // Bind shader and vertex buffers
     wgpuRenderPassEncoderSetVertexBuffer(ctx, 0, fr->VertexBuffer, 0, fr->VertexBufferSize * sizeof(ImDrawVert));

docs/CHANGELOG.txt

diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index 716cd3f..14978c6 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -64,6 +64,8 @@
   - QNX: added QNX Screen backend. (#9492) [@mgorchak-blackberry]
   - SDL2: fixed querying framebuffer scale/density when using Metal without
     going through a SDL_Renderer. (#5592) [@lailoken]
+  - WebGPU: fixed passing non-integer sizes to `wgpuRenderPassEncoderSetViewport()`
+    when when `FramebufferScale` is >1.0f. (#9515, #8628) [@WayU]
 - Examples:
   - SDL2+Metal: create Metal context without using a SDL_Renderer.
   - QNX+OpenGL3, QNX+Vulkan: added QNX Screen examples. (#9492) [@mgorchak-blackberry]