Diff
Modified: trunk/Source/WebCore/ChangeLog (232153 => 232154)
--- trunk/Source/WebCore/ChangeLog 2018-05-24 15:42:20 UTC (rev 232153)
+++ trunk/Source/WebCore/ChangeLog 2018-05-24 16:57:24 UTC (rev 232154)
@@ -1,5 +1,18 @@
2018-05-24 Zalan Bujtas <[email protected]>
+ [LFC] Implement position computation for inflow positioned elements
+ https://bugs.webkit.org/show_bug.cgi?id=185936
+
+ Reviewed by Antti Koivisto.
+
+ * layout/blockformatting/BlockFormattingContext.cpp:
+ (WebCore::Layout::BlockFormattingContext::computeInFlowPositionedPosition const):
+ * layout/blockformatting/BlockFormattingContext.h:
+ * layout/blockformatting/BlockFormattingContextGeometry.cpp:
+ (WebCore::Layout::BlockFormattingContext::Geometry::inFlowPositionedPosition):
+
+2018-05-24 Zalan Bujtas <[email protected]>
+
[LFC] Implement FormattingContext::placeInFlowPositionedChildren
https://bugs.webkit.org/show_bug.cgi?id=185934
Modified: trunk/Source/WebCore/layout/blockformatting/BlockFormattingContext.cpp (232153 => 232154)
--- trunk/Source/WebCore/layout/blockformatting/BlockFormattingContext.cpp 2018-05-24 15:42:20 UTC (rev 232153)
+++ trunk/Source/WebCore/layout/blockformatting/BlockFormattingContext.cpp 2018-05-24 16:57:24 UTC (rev 232154)
@@ -134,6 +134,12 @@
displayBox.setTopLeft(topLeft);
}
+void BlockFormattingContext::computeInFlowPositionedPosition(LayoutContext& layoutContext, const Box& layoutBox, Display::Box& displayBox) const
+{
+ auto topLeft = Geometry::inFlowPositionedPosition(layoutContext, layoutBox);
+ displayBox.setTopLeft(topLeft);
+}
+
void BlockFormattingContext::computeInFlowHeight(LayoutContext& layoutContext, const Box& layoutBox, Display::Box& displayBox) const
{
LayoutUnit computedHeight;
Modified: trunk/Source/WebCore/layout/blockformatting/BlockFormattingContext.h (232153 => 232154)
--- trunk/Source/WebCore/layout/blockformatting/BlockFormattingContext.h 2018-05-24 15:42:20 UTC (rev 232153)
+++ trunk/Source/WebCore/layout/blockformatting/BlockFormattingContext.h 2018-05-24 16:57:24 UTC (rev 232154)
@@ -52,6 +52,7 @@
private:
void computeStaticPosition(LayoutContext&, const Box&, Display::Box&) const override;
+ void computeInFlowPositionedPosition(LayoutContext&, const Box&, Display::Box&) const override;
void computeInFlowWidth(LayoutContext&, const Box&, Display::Box&) const override;
void computeInFlowHeight(LayoutContext&, const Box&, Display::Box&) const override;
@@ -65,6 +66,7 @@
static LayoutUnit inFlowNonReplacedWidth(LayoutContext&, const Box&);
static LayoutPoint staticPosition(LayoutContext&, const Box&);
+ static LayoutPoint inFlowPositionedPosition(LayoutContext&, const Box&);
};
};
Modified: trunk/Source/WebCore/layout/blockformatting/BlockFormattingContextGeometry.cpp (232153 => 232154)
--- trunk/Source/WebCore/layout/blockformatting/BlockFormattingContextGeometry.cpp 2018-05-24 15:42:20 UTC (rev 232153)
+++ trunk/Source/WebCore/layout/blockformatting/BlockFormattingContextGeometry.cpp 2018-05-24 16:57:24 UTC (rev 232154)
@@ -137,7 +137,69 @@
return topLeft;
}
+LayoutPoint BlockFormattingContext::Geometry::inFlowPositionedPosition(LayoutContext& layoutContext, const Box& layoutBox)
+{
+ ASSERT(layoutBox.isInFlowPositioned());
+ // 9.4.3 Relative positioning
+ //
+ // The 'top' and 'bottom' properties move relatively positioned element(s) up or down without changing their size.
+ // Top' moves the boxes down, and 'bottom' moves them up. Since boxes are not split or stretched as a result of 'top' or 'bottom', the used values are always: top = -bottom.
+ //
+ // 1. If both are 'auto', their used values are both '0'.
+ // 2. If one of them is 'auto', it becomes the negative of the other.
+ // 3. If neither is 'auto', 'bottom' is ignored (i.e., the used value of 'bottom' will be minus the value of 'top').
+ auto& displayBox = *layoutContext.displayBoxForLayoutBox(layoutBox);
+ auto& style = layoutBox.style();
+
+ auto top = style.logicalTop();
+ auto bottom = style.logicalBottom();
+ LayoutUnit topDelta;
+
+ if (top.isAuto() && bottom.isAuto()) {
+ // #1
+ topDelta = 0;
+ } else if (top.isAuto()) {
+ // #2
+ topDelta = -bottom.value();
+ } else if (bottom.isAuto()) {
+ // #3 #4
+ topDelta = top.value();
+ }
+
+ // For relatively positioned elements, 'left' and 'right' move the box(es) horizontally, without changing their size.
+ // 'Left' moves the boxes to the right, and 'right' moves them to the left.
+ // Since boxes are not split or stretched as a result of 'left' or 'right', the used values are always: left = -right.
+ //
+ // 1. If both 'left' and 'right' are 'auto' (their initial values), the used values are '0' (i.e., the boxes stay in their original position).
+ // 2. If 'left' is 'auto', its used value is minus the value of 'right' (i.e., the boxes move to the left by the value of 'right').
+ // 3. If 'right' is specified as 'auto', its used value is minus the value of 'left'.
+ // 4. If neither 'left' nor 'right' is 'auto', the position is over-constrained, and one of them has to be ignored.
+ // If the 'direction' property of the containing block is 'ltr', the value of 'left' wins and 'right' becomes -'left'.
+ // If 'direction' of the containing block is 'rtl', 'right' wins and 'left' is ignored.
+ //
+ auto left = style.logicalLeft();
+ auto right = style.logicalRight();
+ LayoutUnit leftDelta;
+
+ if (left.isAuto() && right.isAuto()) {
+ // #1
+ leftDelta = 0;
+ } else if (left.isAuto()) {
+ // #2
+ leftDelta = -right.value();
+ } else if (right.isAuto()) {
+ // #3
+ leftDelta = left.value();
+ } else {
+ // #4
+ // FIXME: take direction into account
+ leftDelta = left.value();
+ }
+
+ return { displayBox.left() + leftDelta, displayBox.top() + topDelta };
}
+
}
+}
#endif
