Nikolay Sivov (@nsivov) commented about dlls/dwrite/tests/font.c:
+ ok(c == RGB(255, 0, 0), "got 0x%08lx\n", c); + + /* Doubled ppdip */ + hr = IDWriteBitmapRenderTarget_SetPixelsPerDip(target, 2.0); + ok(hr == S_OK, "Unexpected hr %#lx.\n", hr); + + SetDCBrushColor(hdc, 0); + SelectObject(hdc, GetStockObject(DC_BRUSH)); + Rectangle(hdc, 0, 0, 400, 400); + hr = IDWriteBitmapRenderTarget_DrawGlyphRun(target, 30.0f, 65.0f, DWRITE_MEASURING_MODE_GDI_NATURAL, + &run, params, RGB(255, 0, 0), &box); + ok(hr == S_OK, "Failed to draw a run, hr %#lx.\n", hr); + c = GetPixel(hdc, 30 + 2, 65 - 2); + ok(c == RGB(0, 0, 0), "got 0x%08lx\n", c); + c = GetPixel(hdc, 30 * 2 + 2, 65 * 2 - 2); + ok(c == RGB(255, 0, 0), "got 0x%08lx\n", c); This looks very unreliable. We could add some special font that has full black rectangle for some glyph, and use that.
-- https://gitlab.winehq.org/wine/wine/-/merge_requests/3718#note_44156