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For the filter indices and wheight calculation, never calculate more

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pixels than can possibly be visible. Clients may pass very large
view rects to layout a zoomed in bitmap. This doesn't only speed things
up, but also avoids a stack overflow in the app_server, as reported in #3166.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@29397 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Stephan Aßmus
2009-03-04 13:46:56 +00:00
parent 6acf774d2d
commit 9801209684
1 changed files with 56 additions and 12 deletions
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src/servers/app/drawing/Painter/Painter.cpp
+56 -12
View File
@@ -1979,6 +1979,26 @@ Painter::_DrawBitmapNearestNeighborCopy32(agg::rendering_buffer& srcBuffer,
uint32 srcWidth = srcBuffer.width();
uint32 srcHeight = srcBuffer.height();
// Do not calculate more filter weights than necessary and also
// keep the stack based allocations reasonably sized
if (fClippingRegion->Frame().IntegerWidth() + 1 < dstWidth)
dstWidth = fClippingRegion->Frame().IntegerWidth() + 1;
if (fClippingRegion->Frame().IntegerHeight() + 1 < dstHeight)
dstHeight = fClippingRegion->Frame().IntegerHeight() + 1;
// When calculating less filter weights than specified by viewRect,
// we need to compensate the offset.
uint32 filterWeightXIndexOffset = 0;
uint32 filterWeightYIndexOffset = 0;
if (fClippingRegion->Frame().left > viewRect.left) {
filterWeightXIndexOffset = fClippingRegion->Frame().left
- viewRect.left;
}
if (fClippingRegion->Frame().top > viewRect.top) {
filterWeightYIndexOffset = fClippingRegion->Frame().top
- viewRect.top;
}
// should not pose a problem with stack overflows
// (needs around 6Kb for 1920x1200)
uint16 xIndices[dstWidth];
@@ -1992,7 +2012,8 @@ Painter::_DrawBitmapNearestNeighborCopy32(agg::rendering_buffer& srcBuffer,
for (uint32 i = 0; i < dstWidth; i++) {
// index into source
uint16 index = (uint16)(i * srcWidth / (srcWidth * xScale));
uint16 index = (uint16)((i + filterWeightXIndexOffset) * srcWidth
/ (srcWidth * xScale));
// round down to get the left pixel
xIndices[i] = index;
// handle cropped source bitmap
@@ -2003,7 +2024,8 @@ Painter::_DrawBitmapNearestNeighborCopy32(agg::rendering_buffer& srcBuffer,
for (uint32 i = 0; i < dstHeight; i++) {
// index into source
uint16 index = (uint16)(i * srcHeight / (srcHeight * yScale));
uint16 index = (uint16)((i + filterWeightYIndexOffset) * srcHeight
/ (srcHeight * yScale));
// round down to get the top pixel
yIndices[i] = index;
// handle cropped source bitmap
@@ -2041,10 +2063,10 @@ Painter::_DrawBitmapNearestNeighborCopy32(agg::rendering_buffer& srcBuffer,
// x and y are needed as indeces into the wheight arrays, so the
// offset into the target buffer needs to be compensated
const int32 xIndexL = x1 - left;
const int32 xIndexR = x2 - left;
y1 -= top;
y2 -= top;
const int32 xIndexL = x1 - left - filterWeightXIndexOffset;
const int32 xIndexR = x2 - left - filterWeightXIndexOffset;
y1 -= top + filterWeightYIndexOffset;
y2 -= top + filterWeightYIndexOffset;
//printf("x: %ld - %ld\n", xIndexL, xIndexR);
//printf("y: %ld - %ld\n", y1, y2);
@@ -2078,6 +2100,26 @@ Painter::_DrawBitmapBilinearCopy32(agg::rendering_buffer& srcBuffer,
uint32 srcWidth = srcBuffer.width();
uint32 srcHeight = srcBuffer.height();
// Do not calculate more filter weights than necessary and also
// keep the stack based allocations reasonably sized
if (fClippingRegion->Frame().IntegerWidth() + 1 < dstWidth)
dstWidth = fClippingRegion->Frame().IntegerWidth() + 1;
if (fClippingRegion->Frame().IntegerHeight() + 1 < dstHeight)
dstHeight = fClippingRegion->Frame().IntegerHeight() + 1;
// When calculating less filter weights than specified by viewRect,
// we need to compensate the offset.
uint32 filterWeightXIndexOffset = 0;
uint32 filterWeightYIndexOffset = 0;
if (fClippingRegion->Frame().left > viewRect.left) {
filterWeightXIndexOffset = fClippingRegion->Frame().left
- viewRect.left;
}
if (fClippingRegion->Frame().top > viewRect.top) {
filterWeightYIndexOffset = fClippingRegion->Frame().top
- viewRect.top;
}
struct FilterInfo {
uint16 index; // index into source bitmap row/column
uint16 weight; // weight of the pixel at index [0..255]
@@ -2114,7 +2156,8 @@ Painter::_DrawBitmapBilinearCopy32(agg::rendering_buffer& srcBuffer,
// to access the rightmost pixel of the source with a weighting
// of 255. This in turn will trigger an optimization in the loop
// that also prevents out of bounds access.
float index = i * (srcWidth - 1) / (srcWidth * xScale - 1);
float index = (i + filterWeightXIndexOffset) * (srcWidth - 1)
/ (srcWidth * xScale - 1);
// round down to get the left pixel
xWeights[i].index = (uint16)index;
xWeights[i].weight = 255 - (uint16)((index - xWeights[i].index) * 255);
@@ -2132,7 +2175,8 @@ Painter::_DrawBitmapBilinearCopy32(agg::rendering_buffer& srcBuffer,
// to access the bottommost pixel of the source with a weighting
// of 255. This in turn will trigger an optimization in the loop
// that also prevents out of bounds access.
float index = i * (srcHeight - 1) / (srcHeight * yScale - 1);
float index = (i + filterWeightYIndexOffset) * (srcHeight - 1)
/ (srcHeight * yScale - 1);
// round down to get the top pixel
yWeights[i].index = (uint16)index;
yWeights[i].weight = 255 - (uint16)((index - yWeights[i].index) * 255);
@@ -2179,10 +2223,10 @@ Painter::_DrawBitmapBilinearCopy32(agg::rendering_buffer& srcBuffer,
// x and y are needed as indeces into the wheight arrays, so the
// offset into the target buffer needs to be compensated
const int32 xIndexL = x1 - left;
const int32 xIndexR = x2 - left;
y1 -= top;
y2 -= top;
const int32 xIndexL = x1 - left - filterWeightXIndexOffset;
const int32 xIndexR = x2 - left - filterWeightXIndexOffset;
y1 -= top + filterWeightYIndexOffset;
y2 -= top + filterWeightYIndexOffset;
//printf("x: %ld - %ld\n", xIndexL, xIndexR);
//printf("y: %ld - %ld\n", y1, y2);