gdiplus: Use float increment instead of calculation to impove perf.

Improves efficiency by using addition instead of float numbers multiplication for destination points. Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=53947

gdiplus: Use float increment instead of calculation to impove perf.
382603af · Bartosz Kosiorek · Alexandre Julliard · 9705fbd4 · 382603af
Commit 382603af authored May 21, 2023 by Bartosz Kosiorek Committed by Alexandre Julliard May 23, 2023
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Showing with 13 additions and 7 deletions

graphics.c dlls/gdiplus/graphics.c +13 -7

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--- a/dlls/gdiplus/graphics.c
+++ b/dlls/gdiplus/graphics.c
@@ -3237,6 +3237,7 @@ GpStatus WINGDIPAPI GdipDrawImagePointsRect(GpGraphics *graphics, GpImage *image
                GpPointF dst_to_src_points[3] = {{0.0, 0.0}, {1.0, 0.0}, {0.0, 1.0}};
                REAL x_dx, x_dy, y_dx, y_dy;
                ARGB *dst_color;
+                GpPointF src_pointf_row, src_pointf;

                m11 = (ptf[1].X - ptf[0].X) / srcwidth;
                m21 = (ptf[2].X - ptf[0].X) / srcheight;
@@ -3266,16 +3267,21 @@ GpStatus WINGDIPAPI GdipDrawImagePointsRect(GpGraphics *graphics, GpImage *image
                    heap_free(src_data);
                    return OutOfMemory;
                }
-
                dst_color = (ARGB*)(dst_data);
-                for (y = dst_area.top; y < dst_area.bottom; y++)
+
+                /* Calculate top left point of transformed image.
+                   It would be used as reference point for adding */
+                src_pointf_row.X = dst_to_src_points[0].X +
+                                   dst_area.left * x_dx + dst_area.top * y_dx;
+                src_pointf_row.Y = dst_to_src_points[0].Y +
+                                   dst_area.left * x_dy + dst_area.top * y_dy;
+
+                for (y = dst_area.top; y < dst_area.bottom;
+                     y++, src_pointf_row.X += y_dx, src_pointf_row.Y += y_dy)
                {
-                    for (x = dst_area.left; x < dst_area.right; x++)
+                    for (x = dst_area.left, src_pointf = src_pointf_row; x < dst_area.right;
+                         x++, src_pointf.X += x_dx, src_pointf.Y += x_dy)
                    {
-                        GpPointF src_pointf;
-                        src_pointf.X = dst_to_src_points[0].X + x * x_dx + y * y_dx;
-                        src_pointf.Y = dst_to_src_points[0].Y + x * x_dy + y * y_dy;
-
                        if (src_pointf.X >= srcx && src_pointf.X < srcx + srcwidth &&
                            src_pointf.Y >= srcy && src_pointf.Y < srcy + srcheight)
                            *dst_color = resample_bitmap_pixel(&src_area, src_data, bitmap->width, bitmap->height, &src_pointf,