1 files changed, 104 insertions, 0 deletions
diff --git a/gfx/2d/BufferEdgePad.cpp b/gfx/2d/BufferEdgePad.cpp
new file mode 100644
index 0000000000..69f508f788
--- /dev/null
+++ b/gfx/2d/BufferEdgePad.cpp
@@ -0,0 +1,104 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "BufferEdgePad.h"
+
+#include "2D.h"     // for DrawTarget
+#include "Point.h"  // for IntSize
+#include "Types.h"  // for SurfaceFormat
+
+#include "nsRegion.h"
+
+namespace mozilla {
+namespace gfx {
+
+void PadDrawTargetOutFromRegion(DrawTarget* aDrawTarget,
+                                const nsIntRegion& aRegion) {
+  struct LockedBits {
+    uint8_t* data;
+    IntSize size;
+    int32_t stride;
+    SurfaceFormat format;
+    static int clamp(int x, int min, int max) {
+      if (x < min) x = min;
+      if (x > max) x = max;
+      return x;
+    }
+
+    static void ensure_memcpy(uint8_t* dst, uint8_t* src, size_t n,
+                              uint8_t* bitmap, int stride, int height) {
+      if (src + n > bitmap + stride * height) {
+        MOZ_CRASH("GFX: long src memcpy");
+      }
+      if (src < bitmap) {
+        MOZ_CRASH("GFX: short src memcpy");
+      }
+      if (dst + n > bitmap + stride * height) {
+        MOZ_CRASH("GFX: long dst mempcy");
+      }
+      if (dst < bitmap) {
+        MOZ_CRASH("GFX: short dst mempcy");
+      }
+    }
+
+    static void visitor(void* closure, VisitSide side, int x1, int y1, int x2,
+                        int y2) {
+      LockedBits* lb = static_cast<LockedBits*>(closure);
+      uint8_t* bitmap = lb->data;
+      const int bpp = gfx::BytesPerPixel(lb->format);
+      const int stride = lb->stride;
+      const int width = lb->size.width;
+      const int height = lb->size.height;
+
+      if (side == VisitSide::TOP) {
+        if (y1 > 0) {
+          x1 = clamp(x1, 0, width - 1);
+          x2 = clamp(x2, 0, width - 1);
+          ensure_memcpy(&bitmap[x1 * bpp + (y1 - 1) * stride],
+                        &bitmap[x1 * bpp + y1 * stride], (x2 - x1) * bpp,
+                        bitmap, stride, height);
+          memcpy(&bitmap[x1 * bpp + (y1 - 1) * stride],
+                 &bitmap[x1 * bpp + y1 * stride], (x2 - x1) * bpp);
+        }
+      } else if (side == VisitSide::BOTTOM) {
+        if (y1 < height) {
+          x1 = clamp(x1, 0, width - 1);
+          x2 = clamp(x2, 0, width - 1);
+          ensure_memcpy(&bitmap[x1 * bpp + y1 * stride],
+                        &bitmap[x1 * bpp + (y1 - 1) * stride], (x2 - x1) * bpp,
+                        bitmap, stride, height);
+          memcpy(&bitmap[x1 * bpp + y1 * stride],
+                 &bitmap[x1 * bpp + (y1 - 1) * stride], (x2 - x1) * bpp);
+        }
+      } else if (side == VisitSide::LEFT) {
+        if (x1 > 0) {
+          while (y1 != y2) {
+            memcpy(&bitmap[(x1 - 1) * bpp + y1 * stride],
+                   &bitmap[x1 * bpp + y1 * stride], bpp);
+            y1++;
+          }
+        }
+      } else if (side == VisitSide::RIGHT) {
+        if (x1 < width) {
+          while (y1 != y2) {
+            memcpy(&bitmap[x1 * bpp + y1 * stride],
+                   &bitmap[(x1 - 1) * bpp + y1 * stride], bpp);
+            y1++;
+          }
+        }
+      }
+    }
+  } lb;
+
+  if (aDrawTarget->LockBits(&lb.data, &lb.size, &lb.stride, &lb.format)) {
+    // we can only pad software targets so if we can't lock the bits don't pad
+    aRegion.VisitEdges(lb.visitor, &lb);
+    aDrawTarget->ReleaseBits(lb.data);
+  }
+}
+
+}  // namespace gfx
+}  // namespace mozilla