fix(gui): make SVG icon rasterization DPI-aware in loadPixmap (#189) #266

forbes · 2026-02-18T18:56:11Z

forbes commented

2026-02-18 18:56:11 +00:00

Summary

BitmapFactory::loadPixmap() rendered all SVGs at a hardcoded 64x64 pixels regardless of display DPI. On HiDPI screens, Qt downscaled these low-resolution pixmaps to the toolbar icon size, producing chunky/aliased icons.

Root Cause

loadPixmap() called pixmapFromSvg(content, QSize(64, 64)) without accounting for the device pixel ratio. A DPI-aware path already existed in the named pixmapFromSvg(const char*, QSizeF) overload, but the generic loadPixmap() path (used by all toolbar icons) never used it.

Fix

Multiply the render size by getMaximumDPR() and tag the resulting pixmap with setDevicePixelRatio(), matching the existing pattern in the named overload. This is a 3-line change in src/Gui/BitmapFactory.cpp.

Testing

Added tests/src/Gui/BitmapFactory.cpp with 3 GTest cases:
- PixmapFromSvgContentRendersAtRequestedSize -- verifies the raw content path
- MaximumDPRIsAtLeastOne -- sanity check on DPR utility
- PixmapFromSvgFileHasCorrectDPR -- end-to-end test: writes SVG to temp dir, loads via pixmap(), verifies DPR and physical size

Verification

Visual inspection on HiDPI display recommended -- toolbar icons should appear crisp rather than chunky/aliased at all preference sizes (16, 24, 32, 48).

Closes #189

## Summary `BitmapFactory::loadPixmap()` rendered all SVGs at a hardcoded 64x64 pixels regardless of display DPI. On HiDPI screens, Qt downscaled these low-resolution pixmaps to the toolbar icon size, producing chunky/aliased icons. ## Root Cause `loadPixmap()` called `pixmapFromSvg(content, QSize(64, 64))` without accounting for the device pixel ratio. A DPI-aware path already existed in the named `pixmapFromSvg(const char*, QSizeF)` overload, but the generic `loadPixmap()` path (used by all toolbar icons) never used it. ## Fix Multiply the render size by `getMaximumDPR()` and tag the resulting pixmap with `setDevicePixelRatio()`, matching the existing pattern in the named overload. This is a 3-line change in `src/Gui/BitmapFactory.cpp`. ## Testing - Added `tests/src/Gui/BitmapFactory.cpp` with 3 GTest cases: - `PixmapFromSvgContentRendersAtRequestedSize` -- verifies the raw content path - `MaximumDPRIsAtLeastOne` -- sanity check on DPR utility - `PixmapFromSvgFileHasCorrectDPR` -- end-to-end test: writes SVG to temp dir, loads via `pixmap()`, verifies DPR and physical size ## Verification Visual inspection on HiDPI display recommended -- toolbar icons should appear crisp rather than chunky/aliased at all preference sizes (16, 24, 32, 48). Closes #189

forbes added 2 commits 2026-02-18 18:56:12 +00:00

fix(gui): make SVG icon rasterization DPI-aware in loadPixmap (#189 ) 99f2a92df4

loadPixmap() rendered all SVGs at a hardcoded 64x64 pixels regardless of
display DPI. On HiDPI screens, Qt then downscaled these low-resolution
pixmaps to the toolbar icon size, producing chunky/aliased icons.

Multiply the render size by getMaximumDPR() and tag the resulting pixmap
with the correct devicePixelRatio, matching the pattern already used in
pixmapFromSvg(const char* name, QSizeF size). This ensures SVGs are
rasterized at the physical resolution needed for crisp display.

test(gui): add BitmapFactory DPI-aware SVG rendering tests (#189 )

Build and Test / build (pull_request) Successful in 29m28s

Details

ea49736549

Three tests for the loadPixmap() DPI fix:
- pixmapFromSvg(content, size) renders at the exact requested size
- getMaximumDPR() returns >= 1.0
- pixmap() loaded from an SVG file has correct devicePixelRatio and
  physical size matching 64 * DPR

forbes merged commit 41669eea8b into main

2026-02-18 18:57:15 +00:00

forbes deleted branch fix/toolbar-icon-dpi-scaling

2026-02-18 18:57:16 +00:00

forbes referenced this issue from a commit

2026-02-18 18:57:17 +00:00

Merge pull request 'fix(gui): make SVG icon rasterization DPI-aware in loadPixmap (#189)' (#266) from fix/toolbar-icon-dpi-scaling into main

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Reference: kindred/create#266