[PATCH v3 0/1] MR3871: gdiplus: implement PixelOffsetMode Half and HighQuality for GdipDrawImagePointsRect

[Bartosz Kosiorek (＠gang65)]

--
  v3:  
https://gitlab.winehq.org/wine/wine/-/merge_requests/3871

[PATCH v3 1/1] gdiplus: implement PixelOffsetMode Half and HighQuality for GdipDrawImagePointsRect

[Bartosz Kosiorek]

From: Bartosz Kosiorek <gang65(a)poczta.onet.pl>

---
 dlls/gdiplus/graphics.c    | 15 +++++++++++++--
 dlls/gdiplus/tests/image.c | 26 +++++++++++++++++---------
 2 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/dlls/gdiplus/graphics.c b/dlls/gdiplus/graphics.c
index 65b33cdc960..bbbf598f0e1 100644
--- a/dlls/gdiplus/graphics.c
+++ b/dlls/gdiplus/graphics.c
@@ -3217,6 +3217,7 @@ GpStatus WINGDIPAPI GdipDrawImagePointsRect(GpGraphics *graphics, GpImage *image
                 GpMatrix dst_to_src;
                 REAL m11, m12, m21, m22, mdx, mdy;
                 REAL x_dx, x_dy, y_dx, y_dy;
+                REAL dst_pixel_offset;
                 ARGB *dst_color;
                 GpPointF src_pointf_row, src_pointf;
 
@@ -3247,12 +3248,22 @@ GpStatus WINGDIPAPI GdipDrawImagePointsRect(GpGraphics *graphics, GpImage *image
                 }
                 dst_color = (ARGB*)(dst_data);
 
+                if ((offset_mode == PixelOffsetModeHalf) ||
+                    (offset_mode == PixelOffsetModeHighQuality))
+                {
+                    // We are checking color in the middle of destination pixel,
+                    // that's why we are adding 0.5 to destination area.
+                    dst_pixel_offset = 0.5;
+                }
+                else
+                    dst_pixel_offset = 0.0;
+
                 /* Calculate top left point of transformed image.
                    It would be used as reference point for adding */
                 src_pointf_row.X = dst_to_src.matrix[4] +
-                                   dst_area.left * x_dx + dst_area.top * y_dx;
+                                   (dst_area.left + dst_pixel_offset) * x_dx + (dst_area.top + dst_pixel_offset) * y_dx;
                 src_pointf_row.Y = dst_to_src.matrix[5] +
-                                   dst_area.left * x_dy + dst_area.top * y_dy;
+                                   (dst_area.left + dst_pixel_offset) * x_dy + (dst_area.top + dst_pixel_offset) * y_dy;
 
                 for (y = dst_area.top; y < dst_area.bottom;
                      y++, src_pointf_row.X += y_dx, src_pointf_row.Y += y_dy)
diff --git a/dlls/gdiplus/tests/image.c b/dlls/gdiplus/tests/image.c
index 18fe8fcba37..b9b3466ea4f 100644
--- a/dlls/gdiplus/tests/image.c
+++ b/dlls/gdiplus/tests/image.c
@@ -4618,8 +4618,10 @@ static void test_DrawImage(void)
     match = memcmp(white_2x2, black_2x2, sizeof(black_2x2)) == 0;
     ok(match, "data should match\n");
     if (!match)
-        trace("%s\n", dbgstr_hexdata(white_2x2, sizeof(white_2x2)));
-
+    {
+        trace("Expected: %s\n", dbgstr_hexdata(black_2x2, sizeof(black_2x2)));
+        trace("Got:      %s\n", dbgstr_hexdata(white_2x2, sizeof(white_2x2)));
+    }
     status = GdipDeleteGraphics(graphics);
     expect(Ok, status);
     status = GdipDisposeImage(u1.image);
@@ -4708,7 +4710,10 @@ static void test_GdipDrawImagePointRect(void)
     match = memcmp(white_2x2, black_2x2, sizeof(black_2x2)) == 0;
     ok(match, "data should match\n");
     if (!match)
-        trace("%s\n", dbgstr_hexdata(white_2x2, sizeof(white_2x2)));
+    {
+        trace("Expected: %s\n", dbgstr_hexdata(black_2x2, sizeof(black_2x2)));
+        trace("Got:      %s\n", dbgstr_hexdata(white_2x2, sizeof(white_2x2)));
+    }
 
     status = GdipDeleteGraphics(graphics);
     expect(Ok, status);
@@ -4825,6 +4830,8 @@ static void test_DrawImage_scale(void)
                                              0xcc,0xcc,0xcc, 0xcc,0xcc,0xcc, 0x40,0x40,0x40, 0x40,0x40,0x40 };
     static const BYTE image_250_half[24] = { 0x40,0x40,0x40, 0x40,0x40,0x40, 0x80,0x80,0x80, 0x80,0x80,0x80,
                                              0x80,0x80,0x80, 0xcc,0xcc,0xcc, 0xcc,0xcc,0xcc, 0x40,0x40,0x40 };
+    static const BYTE image_251_half[24] = { 0x40,0x40,0x40, 0x40,0x40,0x40, 0x40,0x40,0x40, 0x80,0x80,0x80,
+                                             0x80,0x80,0x80, 0xcc,0xcc,0xcc, 0xcc,0xcc,0xcc, 0xcc,0xcc,0xcc };
     static const struct test_data
     {
         REAL scale_x;
@@ -4851,19 +4858,20 @@ static void test_DrawImage_scale(void)
 
         { 0.8, PixelOffsetModeHalf, image_080 }, /* 14 */
         { 1.0, PixelOffsetModeHalf, image_100 },
-        { 1.2, PixelOffsetModeHalf, image_120_half, TRUE },
+        { 1.2, PixelOffsetModeHalf, image_120_half },
         { 1.5, PixelOffsetModeHalf, image_150_half, TRUE },
-        { 1.8, PixelOffsetModeHalf, image_180_half, TRUE },
-        { 2.0, PixelOffsetModeHalf, image_200_half, TRUE },
+        { 1.8, PixelOffsetModeHalf, image_180_half },
+        { 2.0, PixelOffsetModeHalf, image_200_half },
         { 2.5, PixelOffsetModeHalf, image_250_half, TRUE },
 
         { 0.8, PixelOffsetModeHighQuality, image_080 }, /* 21 */
         { 1.0, PixelOffsetModeHighQuality, image_100 },
-        { 1.2, PixelOffsetModeHighQuality, image_120_half, TRUE },
+        { 1.2, PixelOffsetModeHighQuality, image_120_half },
         { 1.5, PixelOffsetModeHighQuality, image_150_half, TRUE },
-        { 1.8, PixelOffsetModeHighQuality, image_180_half, TRUE },
-        { 2.0, PixelOffsetModeHighQuality, image_200_half, TRUE },
+        { 1.8, PixelOffsetModeHighQuality, image_180_half },
+        { 2.0, PixelOffsetModeHighQuality, image_200_half },
         { 2.5, PixelOffsetModeHighQuality, image_250_half, TRUE },
+        { 2.51, PixelOffsetModeHighQuality, image_251_half },
     };
     BYTE src_2x1[6] = { 0x80,0x80,0x80, 0xcc,0xcc,0xcc };
     BYTE dst_8x1[24];
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/3871