[PATCH v2 0/2] MR10724: gdiplus: Elide empty spans.

[Conor McCarthy (＠cmccarthy)]

We assume a span is never empty and therefore can never begin at the
right bound. An empty span there can break the requirement in
combine_regions_to_spans() that current span Y coordinates are never less
than the loop Y coordinate. Empty spans also break the in_left and
in_right calculation.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=59678

The added test will assert without the fix.

--
  v2: gdiplus/tests: Test a region intersect which produces empty spans.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10724

[PATCH v2 1/2] gdiplus: Elide empty spans.

[Conor McCarthy]

From: Conor McCarthy <[e-mail]>

We assume a span is never empty and therefore can never begin at the
right bound. An empty span there can break the requirement in
combine_regions_to_spans() that current span Y coordinates are never less
than the loop Y coordinate. Empty spans also break the in_left and
in_right calculation.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=59678
---
 dlls/gdiplus/region.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/dlls/gdiplus/region.c b/dlls/gdiplus/region.c
index e430308685b..0969aa6aacb 100644
--- a/dlls/gdiplus/region.c
+++ b/dlls/gdiplus/region.c
@@ -2261,6 +2261,10 @@ static GpStatus edge_list_to_spans_alternate(struct edge_list *edges, struct spa
 
         assert(edge[0].y == edge[1].y);
 
+        /* edges can be collapsed to the left or right bound, making an empty span */
+        if (edge[0].x == edge[1].x)
+            continue;
+
         span = &spans->spans[spans->length++];
         span->x[0] = edge[0].x;
         span->x[1] = edge[1].x;
-- 
GitLab


https://gitlab.winehq.org/wine/wine/-/merge_requests/10724

[PATCH v2 2/2] gdiplus/tests: Test a region intersect which produces empty spans.

[Conor McCarthy]

From: Conor McCarthy <[e-mail]>

---
 dlls/gdiplus/tests/region.c | 51 +++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/dlls/gdiplus/tests/region.c b/dlls/gdiplus/tests/region.c
index 00837096092..bbba50a8080 100644
--- a/dlls/gdiplus/tests/region.c
+++ b/dlls/gdiplus/tests/region.c
@@ -2727,6 +2727,56 @@ static void test_rounding(void)
     GdipDeleteMatrix(matrix);
 }
 
+static void test_empty_spans(void)
+{
+    GpStatus status;
+    GpGraphics *graphics;
+    GpBitmap *bitmap;
+    GpPath *path, *path2;
+    const GpPointF inside_path_points[] = { { 20, 20 }, { 80, 20 }, { 80, 80 } };
+    const GpPointF outside_path_points[] = { { 100, 20 }, { 101, 20 }, { 101, 80 } };
+    GpRegion *region;
+    GpBrush *brush;
+
+    status = GdipCreateBitmapFromScan0(100, 100, 400, PixelFormat32bppARGB, NULL, &bitmap);
+    expect(Ok, status);
+
+    status = GdipGetImageGraphicsContext((GpImage*)bitmap, &graphics);
+    expect(Ok, status);
+
+    status = GdipCreatePath(FillModeAlternate, &path);
+    expect(Ok, status);
+    status = GdipAddPathPolygon(path, inside_path_points, ARRAY_SIZE(inside_path_points));
+    expect(Ok, status);
+
+    status = GdipCreatePath(FillModeAlternate, &path2);
+    expect(Ok, status);
+    /* add a path inside the device bounds and one outside,
+     * resulting in an empty span at the end of each scanline */
+    status = GdipAddPathPolygon(path2, inside_path_points, ARRAY_SIZE(inside_path_points));
+    expect(Ok, status);
+    status = GdipAddPathPolygon(path2, outside_path_points, ARRAY_SIZE(outside_path_points));
+    expect(Ok, status);
+
+    status = GdipCreateRegionPath(path, ®ion);
+    expect(Ok, status);
+    status = GdipCombineRegionPath(region, path2, CombineModeIntersect);
+    expect(Ok, status);
+
+    status = GdipCreateSolidFill(0xffffffff, (GpSolidFill**)&brush);
+    expect(Ok, status);
+
+    status = GdipFillRegion(graphics, brush, region);
+    expect(Ok, status);
+
+    GdipDeleteBrush(brush);
+    GdipDeleteRegion(region);
+    GdipDeletePath(path2);
+    GdipDeletePath(path);
+    GdipDisposeImage((GpImage*)bitmap);
+    GdipDeleteGraphics(graphics);
+}
+
 START_TEST(region)
 {
     struct GdiplusStartupInput gdiplusStartupInput;
@@ -2763,6 +2813,7 @@ START_TEST(region)
     test_GdipCreateRegionRgnData();
     test_incombinedregion();
     test_rounding();
+    test_empty_spans();
 
     GdiplusShutdown(gdiplusToken);
 }
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/10724

[PATCH v2 0/2] MR10724: gdiplus: Elide empty spans. - approved

[Esme Povirk (＠madewokherd)]

This merge request was approved by Esme Povirk.
-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10724