[PATCH 0/1] MR3718: dwrite: Fix incorrect position of glyph when using BitmapRenderTarget in HiDPI

[Tingzhong Luo (＠tzluo)]

The "GdiInterop" is a sample application (source code is avaiable in [Github][source_code], relative guide in [MSDN][msdn_guide]) that demostracts how to display DirectWrite text on a GDI surface. After set dpi to 168 in `winecfg`, and run sample application with wine, the font size is normal, but the position of glyph is incorrect.

| Dpi: 96          | Dpi: 168          |
|:----------------:|:-----------------:|
| ![ss1][sc_96dpi] | ![ss2][sc_168dpi] |

There is the sample application after compile: [Release_x64.tar.gz](/uploads/c70e32824efcaa5d16ab39bbb4b86e30/Release_x64.tar.gz)

After change transform matrix that pass to `IDWriteFactory7_CreateGlyphRunAnalysis`, it can display glyph correctly.

[source_code]: https://github.com/microsoft/Windows-classic-samples/blob/main/Samples/Win7S...
[msdn_guide]: https://learn.microsoft.com/en-us/windows/win32/directwrite/render-to-a-gdi-...
[sc_96dpi]: /uploads/59cc343cfaa025f4ff4c32a84ab8cfeb/图片.png
[sc_168dpi]: /uploads/938be653362bb6ac58471b69ab66099a/图片.png

[PATCH 1/1] dwrite: Fix incorrect position of glyph when rendering with BitmapRenderTarget in HiDPI

[Tingzhong Luo]

From: Tingzhong Luo

Signed-off-by: Tingzhong Luo 
---
 dlls/dwrite/gdiinterop.c | 10 +++++----
 dlls/dwrite/tests/font.c | 44 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/dlls/dwrite/gdiinterop.c b/dlls/dwrite/gdiinterop.c
index 5b542d93e32..764ddf1a4df 100644
--- a/dlls/dwrite/gdiinterop.c
+++ b/dlls/dwrite/gdiinterop.c
@@ -347,7 +347,7 @@ static HRESULT WINAPI rendertarget_DrawGlyphRun(IDWriteBitmapRenderTarget1 *ifac
     DWRITE_RENDERING_MODE1 rendermode;
     DWRITE_GRID_FIT_MODE gridfitmode;
     DWRITE_TEXTURE_TYPE texturetype;
-    DWRITE_GLYPH_RUN scaled_run;
+    DWRITE_MATRIX scaled_matrix;
     IDWriteFontFace3 *fontface;
     RECT target_rect, bounds;
     HRESULT hr;
@@ -429,9 +429,10 @@ static HRESULT WINAPI rendertarget_DrawGlyphRun(IDWriteBitmapRenderTarget1 *ifac
         return hr;
     }

-    scaled_run = *run;
-    scaled_run.fontEmSize *= target->ppdip;
-    hr = IDWriteFactory7_CreateGlyphRunAnalysis(target->factory, &scaled_run, &target->m, rendermode, measuring_mode,
+    scaled_matrix = target->m;
+    scaled_matrix.m11 *= target->ppdip;
+    scaled_matrix.m22 *= target->ppdip;
+    hr = IDWriteFactory7_CreateGlyphRunAnalysis(target->factory, run, &scaled_matrix, rendermode, measuring_mode,
             gridfitmode, target->antialiasmode, originX, originY, &analysis);
     if (FAILED(hr))
     {
@@ -451,6 +452,7 @@ static HRESULT WINAPI rendertarget_DrawGlyphRun(IDWriteBitmapRenderTarget1 *ifac
         }
         texturetype = DWRITE_TEXTURE_CLEARTYPE_3x1;
     }
+    if (bbox_ret) *bbox_ret = bounds;

if (IntersectRect(&target_rect, &target_rect, &bounds))
     {
diff --git a/dlls/dwrite/tests/font.c b/dlls/dwrite/tests/font.c
index 81008db6f23..535c67558bd 100644
--- a/dlls/dwrite/tests/font.c
+++ b/dlls/dwrite/tests/font.c
@@ -1225,6 +1225,7 @@ static void test_CreateBitmapRenderTarget(void)
     SIZE size;
     ULONG ref;
     UINT32 ch;
+    RECT box;
     HDC hdc;
     int ret;

@@ -1507,6 +1508,49 @@ static void test_CreateBitmapRenderTarget(void)
         &run, params, RGB(255, 0, 0), NULL);
     ok(hr == S_OK, "Failed to draw a run, hr %#lx.\n", hr);

+   hr = IDWriteBitmapRenderTarget_SetPixelsPerDip(target, 1.0);
+   ok(hr == S_OK, "Unexpected hr %#lx.\n", hr);
+
+   /* Got render bounds if not intersect to render target */
+   memset(&box, 0, sizeof(box));
+   hr = IDWriteBitmapRenderTarget_DrawGlyphRun(target, 0.0f, 0.0f, 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);
+   ok(box.right - box.left > 0, "got %ld\n", box.right - box.left);
+   ok(box.bottom - box.top > 0, "got %ld\n", box.bottom - box.top);
+
+    /* Check glyph position */
+    run.fontEmSize = 30.0f;
+    hdc = IDWriteBitmapRenderTarget_GetMemoryDC(target);
+    ok(hdc != NULL, "got %p\n", hdc);
+
+    hr = IDWriteBitmapRenderTarget_Resize(target, 400, 400);
+    ok(hr == S_OK, "Failed to resize target, 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(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);
+
     IDWriteRenderingParams_Release(params);

/* Zero sized target returns earlier. */

[Nikolay Sivov (＠nsivov)]

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.

[Nikolay Sivov (＠nsivov)]

Nikolay Sivov (@nsivov) commented about dlls/dwrite/gdiinterop.c:
>      return hr;
>  }
>
> - scaled_run = *run;
> - scaled_run.fontEmSize *= target->ppdip;
> - hr = IDWriteFactory7_CreateGlyphRunAnalysis(target->factory, &scaled_run, &target->m, rendermode, measuring_mode,
> - scaled_matrix = target->m;
> - scaled_matrix.m11 *= target->ppdip;
> - scaled_matrix.m22 *= target->ppdip;
> - hr = IDWriteFactory7_CreateGlyphRunAnalysis(target->factory, run, &scaled_matrix, rendermode, measuring_mode,

As I recall the idea was that bumping fontEmSize is more desirable than scaling outlines up, using smaller size. I think this will need some more testing for CreateGlyphRunAnalysis() itself. I haven't tried, but differences might be easier to spot in aliased mode.

[Nikolay Sivov (＠nsivov)]

Nikolay Sivov (@nsivov) commented about dlls/dwrite/gdiinterop.c:
>      }
>      texturetype = DWRITE_TEXTURE_CLEARTYPE_3x1;
>  }
> - if (bbox_ret) *bbox_ret = bounds;

This one should be a separate change.