void RenderMultiColumnSet::collectLayerFragments(LayerFragments& fragments, const LayoutRect& layerBoundingBox, const LayoutRect& dirtyRect)
{
// Let's start by introducing the different coordinate systems involved here. They are different
// in how they deal with writing modes and columns. RenderLayer rectangles tend to be more
// physical than the rectangles used in RenderObject & co.
//
// The two rectangles passed to this method are physical, except that we pretend that there's
// only one long column (that's the flow thread). They are relative to the top left corner of
// the flow thread. All rectangles being compared to the dirty rect also need to be in this
// coordinate system.
//
// Then there's the output from this method - the stuff we put into the list of fragments. The
// translationOffset point is the actual physical translation required to get from a location in
// the flow thread to a location in some column. The paginationClip rectangle is in the same
// coordinate system as the two rectangles passed to this method (i.e. physical, in flow thread
// coordinates, pretending that there's only one long column).
//
// All other rectangles in this method are slightly less physical, when it comes to how they are
// used with different writing modes, but they aren't really logical either. They are just like
// RenderBox::frameRect(). More precisely, the sizes are physical, and the inline direction
// coordinate is too, but the block direction coordinate is always "logical top". These
// rectangles also pretend that there's only one long column, i.e. they are for the flow thread.
//
// To sum up: input and output from this method are "physical" RenderLayer-style rectangles and
// points, while inside this method we mostly use the RenderObject-style rectangles (with the
// block direction coordinate always being logical top).
// Put the layer bounds into flow thread-local coordinates by flipping it first. Since we're in
// a renderer, most rectangles are represented this way.
LayoutRect layerBoundsInFlowThread(layerBoundingBox);
flowThread()->flipForWritingMode(layerBoundsInFlowThread);
// Now we can compare with the flow thread portions owned by each column. First let's
// see if the rect intersects our flow thread portion at all.
LayoutRect clippedRect(layerBoundsInFlowThread);
clippedRect.intersect(RenderRegion::flowThreadPortionOverflowRect());
if (clippedRect.isEmpty())
return;
// Now we know we intersect at least one column. Let's figure out the logical top and logical
// bottom of the area we're checking.
LayoutUnit layerLogicalTop = isHorizontalWritingMode() ? layerBoundsInFlowThread.y() : layerBoundsInFlowThread.x();
LayoutUnit layerLogicalBottom = (isHorizontalWritingMode() ? layerBoundsInFlowThread.maxY() : layerBoundsInFlowThread.maxX()) - 1;
// Figure out the start and end columns and only check within that range so that we don't walk the
// entire column set.
unsigned startColumn = columnIndexAtOffset(layerLogicalTop);
unsigned endColumn = columnIndexAtOffset(layerLogicalBottom);
LayoutUnit colLogicalWidth = computedColumnWidth();
LayoutUnit colGap = columnGap();
unsigned colCount = columnCount();
RenderBlockFlow* parentFlow = toRenderBlockFlow(parent());
bool progressionReversed = parentFlow->multiColumnFlowThread()->progressionIsReversed();
bool progressionIsInline = parentFlow->multiColumnFlowThread()->progressionIsInline();
LayoutUnit initialBlockOffset = initialBlockOffsetForPainting();
for (unsigned i = startColumn; i <= endColumn; i++) {
// Get the portion of the flow thread that corresponds to this column.
LayoutRect flowThreadPortion = flowThreadPortionRectAt(i);
// Now get the overflow rect that corresponds to the column.
LayoutRect flowThreadOverflowPortion = flowThreadPortionOverflowRect(flowThreadPortion, i, colCount, colGap);
// In order to create a fragment we must intersect the portion painted by this column.
LayoutRect clippedRect(layerBoundsInFlowThread);
clippedRect.intersect(flowThreadOverflowPortion);
if (clippedRect.isEmpty())
continue;
// We also need to intersect the dirty rect. We have to apply a translation and shift based off
// our column index.
LayoutPoint translationOffset;
LayoutUnit inlineOffset = progressionIsInline ? i * (colLogicalWidth + colGap) : LayoutUnit();
bool leftToRight = style().isLeftToRightDirection() ^ progressionReversed;
if (!leftToRight) {
inlineOffset = -inlineOffset;
if (progressionReversed)
inlineOffset += contentLogicalWidth() - colLogicalWidth;
}
translationOffset.setX(inlineOffset);
LayoutUnit blockOffset = initialBlockOffset + (isHorizontalWritingMode() ? -flowThreadPortion.y() : -flowThreadPortion.x());
if (!progressionIsInline) {
if (!progressionReversed)
blockOffset = i * colGap;
else
blockOffset -= i * (computedColumnHeight() + colGap);
}
if (isFlippedBlocksWritingMode(style().writingMode()))
blockOffset = -blockOffset;
translationOffset.setY(blockOffset);
if (!isHorizontalWritingMode())
translationOffset = translationOffset.transposedPoint();
// FIXME: The translation needs to include the multicolumn set's content offset within the
// multicolumn block as well. This won't be an issue until we start creating multiple multicolumn sets.
// Shift the dirty rect to be in flow thread coordinates with this translation applied.
LayoutRect translatedDirtyRect(dirtyRect);
translatedDirtyRect.moveBy(-translationOffset);
// See if we intersect the dirty rect.
clippedRect = layerBoundingBox;
clippedRect.intersect(translatedDirtyRect);
if (clippedRect.isEmpty())
continue;
// Something does need to paint in this column. Make a fragment now and supply the physical translation
// offset and the clip rect for the column with that offset applied.
LayerFragment fragment;
fragment.paginationOffset = translationOffset;
LayoutRect flippedFlowThreadOverflowPortion(flowThreadOverflowPortion);
// Flip it into more a physical (RenderLayer-style) rectangle.
flowThread()->flipForWritingMode(flippedFlowThreadOverflowPortion);
fragment.paginationClip = flippedFlowThreadOverflowPortion;
fragments.append(fragment);
}
}
void RenderMultiColumnSet::collectLayerFragments(LayerFragments& fragments, const LayoutRect& layerBoundingBox, const LayoutRect& dirtyRect)
{
// The two rectangles passed to this method are physical, except that we pretend that there's
// only one long column (that's how a flow thread works).
//
// Then there's the output from this method - the stuff we put into the list of fragments. The
// fragment.paginationOffset point is the actual physical translation required to get from a
// location in the flow thread to a location in a given column. The fragment.paginationClip
// rectangle, on the other hand, is in the same coordinate system as the two rectangles passed
// to this method (flow thread coordinates).
//
// All other rectangles in this method are sized physically, and the inline direction coordinate
// is physical too, but the block direction coordinate is "logical top". This is the same as
// e.g. RenderBox::frameRect(). These rectangles also pretend that there's only one long column,
// i.e. they are for the flow thread.
// Put the layer bounds into flow thread-local coordinates by flipping it first. Since we're in
// a renderer, most rectangles are represented this way.
LayoutRect layerBoundsInFlowThread(layerBoundingBox);
flowThread()->flipForWritingMode(layerBoundsInFlowThread);
// Now we can compare with the flow thread portions owned by each column. First let's
// see if the rect intersects our flow thread portion at all.
LayoutRect clippedRect(layerBoundsInFlowThread);
clippedRect.intersect(RenderRegion::flowThreadPortionOverflowRect());
if (clippedRect.isEmpty())
return;
// Now we know we intersect at least one column. Let's figure out the logical top and logical
// bottom of the area we're checking.
LayoutUnit layerLogicalTop = isHorizontalWritingMode() ? layerBoundsInFlowThread.y() : layerBoundsInFlowThread.x();
LayoutUnit layerLogicalBottom = (isHorizontalWritingMode() ? layerBoundsInFlowThread.maxY() : layerBoundsInFlowThread.maxX()) - 1;
// Figure out the start and end columns and only check within that range so that we don't walk the
// entire column set.
unsigned startColumn = columnIndexAtOffset(layerLogicalTop);
unsigned endColumn = columnIndexAtOffset(layerLogicalBottom);
LayoutUnit colLogicalWidth = computedColumnWidth();
LayoutUnit colGap = columnGap();
unsigned colCount = columnCount();
for (unsigned i = startColumn; i <= endColumn; i++) {
// Get the portion of the flow thread that corresponds to this column.
LayoutRect flowThreadPortion = flowThreadPortionRectAt(i);
// Now get the overflow rect that corresponds to the column.
LayoutRect flowThreadOverflowPortion = flowThreadPortionOverflowRect(flowThreadPortion, i, colCount, colGap);
// In order to create a fragment we must intersect the portion painted by this column.
LayoutRect clippedRect(layerBoundsInFlowThread);
clippedRect.intersect(flowThreadOverflowPortion);
if (clippedRect.isEmpty())
continue;
// We also need to intersect the dirty rect. We have to apply a translation and shift based off
// our column index.
LayoutPoint translationOffset;
LayoutUnit inlineOffset = i * (colLogicalWidth + colGap);
if (!style()->isLeftToRightDirection())
inlineOffset = -inlineOffset;
translationOffset.setX(inlineOffset);
LayoutUnit blockOffset = isHorizontalWritingMode() ? -flowThreadPortion.y() : -flowThreadPortion.x();
if (isFlippedBlocksWritingMode(style()->writingMode()))
blockOffset = -blockOffset;
translationOffset.setY(blockOffset);
if (!isHorizontalWritingMode())
translationOffset = translationOffset.transposedPoint();
// FIXME: The translation needs to include the multicolumn set's content offset within the
// multicolumn block as well. This won't be an issue until we start creating multiple multicolumn sets.
// Shift the dirty rect to be in flow thread coordinates with this translation applied.
LayoutRect translatedDirtyRect(dirtyRect);
translatedDirtyRect.moveBy(-translationOffset);
// See if we intersect the dirty rect.
clippedRect = layerBoundingBox;
clippedRect.intersect(translatedDirtyRect);
if (clippedRect.isEmpty())
continue;
// Something does need to paint in this column. Make a fragment now and supply the physical translation
// offset and the clip rect for the column with that offset applied.
LayerFragment fragment;
fragment.paginationOffset = translationOffset;
LayoutRect flippedFlowThreadOverflowPortion(flowThreadOverflowPortion);
// Flip it into more a physical (RenderLayer-style) rectangle.
flowThread()->flipForWritingMode(flippedFlowThreadOverflowPortion);
fragment.paginationClip = flippedFlowThreadOverflowPortion;
fragments.append(fragment);
}
}
void RenderMultiColumnSet::collectLayerFragments(LayerFragments& fragments, const LayoutRect& layerBoundingBox, const LayoutRect& dirtyRect)
{
// Put the layer bounds into flow thread-local coordinates by flipping it first.
LayoutRect layerBoundsInFlowThread(layerBoundingBox);
flowThread()->flipForWritingMode(layerBoundsInFlowThread);
// Do the same for the dirty rect.
LayoutRect dirtyRectInFlowThread(dirtyRect);
flowThread()->flipForWritingMode(dirtyRectInFlowThread);
// Now we can compare with the flow thread portions owned by each column. First let's
// see if the rect intersects our flow thread portion at all.
LayoutRect clippedRect(layerBoundsInFlowThread);
clippedRect.intersect(RenderRegion::flowThreadPortionOverflowRect());
if (clippedRect.isEmpty())
return;
// Now we know we intersect at least one column. Let's figure out the logical top and logical
// bottom of the area we're checking.
LayoutUnit layerLogicalTop = isHorizontalWritingMode() ? layerBoundsInFlowThread.y() : layerBoundsInFlowThread.x();
LayoutUnit layerLogicalBottom = (isHorizontalWritingMode() ? layerBoundsInFlowThread.maxY() : layerBoundsInFlowThread.maxX()) - 1;
// Figure out the start and end columns and only check within that range so that we don't walk the
// entire column set.
unsigned startColumn = columnIndexAtOffset(layerLogicalTop);
unsigned endColumn = columnIndexAtOffset(layerLogicalBottom);
LayoutUnit colLogicalWidth = computedColumnWidth();
LayoutUnit colGap = columnGap();
unsigned colCount = columnCount();
for (unsigned i = startColumn; i <= endColumn; i++) {
// Get the portion of the flow thread that corresponds to this column.
LayoutRect flowThreadPortion = flowThreadPortionRectAt(i);
// Now get the overflow rect that corresponds to the column.
LayoutRect flowThreadOverflowPortion = flowThreadPortionOverflowRect(flowThreadPortion, i, colCount, colGap);
// In order to create a fragment we must intersect the portion painted by this column.
LayoutRect clippedRect(layerBoundsInFlowThread);
clippedRect.intersect(flowThreadOverflowPortion);
if (clippedRect.isEmpty())
continue;
// We also need to intersect the dirty rect. We have to apply a translation and shift based off
// our column index.
LayoutPoint translationOffset;
LayoutUnit inlineOffset = i * (colLogicalWidth + colGap);
if (!style()->isLeftToRightDirection())
inlineOffset = -inlineOffset;
translationOffset.setX(inlineOffset);
LayoutUnit blockOffset = isHorizontalWritingMode() ? -flowThreadPortion.y() : -flowThreadPortion.x();
if (isFlippedBlocksWritingMode(style()->writingMode()))
blockOffset = -blockOffset;
translationOffset.setY(blockOffset);
if (!isHorizontalWritingMode())
translationOffset = translationOffset.transposedPoint();
// FIXME: The translation needs to include the multicolumn set's content offset within the
// multicolumn block as well. This won't be an issue until we start creating multiple multicolumn sets.
// Shift the dirty rect to be in flow thread coordinates with this translation applied.
LayoutRect translatedDirtyRect(dirtyRectInFlowThread);
translatedDirtyRect.moveBy(-translationOffset);
// See if we intersect the dirty rect.
clippedRect = layerBoundsInFlowThread;
clippedRect.intersect(translatedDirtyRect);
if (clippedRect.isEmpty())
continue;
// Something does need to paint in this column. Make a fragment now and supply the physical translation
// offset and the clip rect for the column with that offset applied.
LayerFragment fragment;
fragment.paginationOffset = translationOffset;
LayoutRect flippedFlowThreadOverflowPortion(flowThreadOverflowPortion);
flipForWritingMode(flippedFlowThreadOverflowPortion);
fragment.paginationClip = flippedFlowThreadOverflowPortion;
fragments.append(fragment);
}
}