gfx/2d/BufferEdgePad.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "BufferEdgePad.h"
   8
   9 #include "2D.h"     // for DrawTarget
  10 #include "Point.h"  // for IntSize
  11 #include "Types.h"  // for SurfaceFormat
  12
  13 #include "nsRegion.h"
  14
  15 namespace mozilla {
  16 namespace gfx {
  17
  18 void PadDrawTargetOutFromRegion(DrawTarget* aDrawTarget,
  19                                 const nsIntRegion& aRegion) {
  20   struct LockedBits {
  21     uint8_t* data;
  22     IntSize size;
  23     int32_t stride;
  24     SurfaceFormat format;
  25     static int clamp(int x, int min, int max) {
  26       if (x < min) x = min;
  27       if (x > max) x = max;
  28       return x;
  29     }
  30
  31     static void ensure_memcpy(uint8_t* dst, uint8_t* src, size_t n,
  32                               uint8_t* bitmap, int stride, int height) {
  33       if (src + n > bitmap + stride * height) {
  34         MOZ_CRASH("GFX: long src memcpy");
  35       }
  36       if (src < bitmap) {
  37         MOZ_CRASH("GFX: short src memcpy");
  38       }
  39       if (dst + n > bitmap + stride * height) {
  40         MOZ_CRASH("GFX: long dst mempcy");
  41       }
  42       if (dst < bitmap) {
  43         MOZ_CRASH("GFX: short dst mempcy");
  44       }
  45     }
  46
  47     static void visitor(void* closure, VisitSide side, int x1, int y1, int x2,
  48                         int y2) {
  49       LockedBits* lb = static_cast<LockedBits*>(closure);
  50       uint8_t* bitmap = lb->data;
  51       const int bpp = gfx::BytesPerPixel(lb->format);
  52       const int stride = lb->stride;
  53       const int width = lb->size.width;
  54       const int height = lb->size.height;
  55
  56       if (side == VisitSide::TOP) {
  57         if (y1 > 0) {
  58           x1 = clamp(x1, 0, width - 1);
  59           x2 = clamp(x2, 0, width - 1);
  60           ensure_memcpy(&bitmap[x1 * bpp + (y1 - 1) * stride],
  61                         &bitmap[x1 * bpp + y1 * stride], (x2 - x1) * bpp,
  62                         bitmap, stride, height);
  63           memcpy(&bitmap[x1 * bpp + (y1 - 1) * stride],
  64                  &bitmap[x1 * bpp + y1 * stride], (x2 - x1) * bpp);
  65         }
  66       } else if (side == VisitSide::BOTTOM) {
  67         if (y1 < height) {
  68           x1 = clamp(x1, 0, width - 1);
  69           x2 = clamp(x2, 0, width - 1);
  70           ensure_memcpy(&bitmap[x1 * bpp + y1 * stride],
  71                         &bitmap[x1 * bpp + (y1 - 1) * stride], (x2 - x1) * bpp,
  72                         bitmap, stride, height);
  73           memcpy(&bitmap[x1 * bpp + y1 * stride],
  74                  &bitmap[x1 * bpp + (y1 - 1) * stride], (x2 - x1) * bpp);
  75         }
  76       } else if (side == VisitSide::LEFT) {
  77         if (x1 > 0) {
  78           while (y1 != y2) {
  79             memcpy(&bitmap[(x1 - 1) * bpp + y1 * stride],
  80                    &bitmap[x1 * bpp + y1 * stride], bpp);
  81             y1++;
  82           }
  83         }
  84       } else if (side == VisitSide::RIGHT) {
  85         if (x1 < width) {
  86           while (y1 != y2) {
  87             memcpy(&bitmap[x1 * bpp + y1 * stride],
  88                    &bitmap[(x1 - 1) * bpp + y1 * stride], bpp);
  89             y1++;
  90           }
  91         }
  92       }
  93     }
  94   } lb;
  95
  96   if (aDrawTarget->LockBits(&lb.data, &lb.size, &lb.stride, &lb.format)) {
  97     // we can only pad software targets so if we can't lock the bits don't pad
  98     aRegion.VisitEdges(lb.visitor, &lb);
  99     aDrawTarget->ReleaseBits(lb.data);
 100   }
 101 }
 102
 103 }  // namespace gfx
 104 }  // namespace mozilla