1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/layout/generic/TextOverflow.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,241 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */
1.6 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#ifndef TextOverflow_h_
1.11 +#define TextOverflow_h_
1.12 +
1.13 +#include "nsDisplayList.h"
1.14 +#include "nsTHashtable.h"
1.15 +#include "mozilla/Likely.h"
1.16 +#include <algorithm>
1.17 +
1.18 +class nsIScrollableFrame;
1.19 +class gfxTextRun;
1.20 +class nsLineBox;
1.21 +
1.22 +namespace mozilla {
1.23 +namespace css {
1.24 +
1.25 +/**
1.26 + * A class for rendering CSS3 text-overflow.
1.27 + * Usage:
1.28 + * 1. allocate an object using WillProcessLines
1.29 + * 2. then call ProcessLine for each line you are building display lists for
1.30 + */
1.31 +class TextOverflow {
1.32 + public:
1.33 + /**
1.34 + * Allocate an object for text-overflow processing.
1.35 + * @return nullptr if no processing is necessary. The caller owns the object.
1.36 + */
1.37 + static TextOverflow* WillProcessLines(nsDisplayListBuilder* aBuilder,
1.38 + nsIFrame* aBlockFrame);
1.39 + /**
1.40 + * Analyze the display lists for text overflow and what kind of item is at
1.41 + * the content edges. Add display items for text-overflow markers as needed
1.42 + * and remove or clip items that would overlap a marker.
1.43 + */
1.44 + void ProcessLine(const nsDisplayListSet& aLists, nsLineBox* aLine);
1.45 +
1.46 + /**
1.47 + * Get the resulting text-overflow markers (the list may be empty).
1.48 + * @return a DisplayList containing any text-overflow markers.
1.49 + */
1.50 + nsDisplayList& GetMarkers() { return mMarkerList; }
1.51 +
1.52 + /**
1.53 + * @return true if aBlockFrame needs analysis for text overflow.
1.54 + */
1.55 + static bool CanHaveTextOverflow(nsDisplayListBuilder* aBuilder,
1.56 + nsIFrame* aBlockFrame);
1.57 +
1.58 + typedef nsTHashtable<nsPtrHashKey<nsIFrame> > FrameHashtable;
1.59 +
1.60 + protected:
1.61 + TextOverflow() {}
1.62 + void Init(nsDisplayListBuilder* aBuilder,
1.63 + nsIFrame* aBlockFrame);
1.64 +
1.65 + struct AlignmentEdges {
1.66 + AlignmentEdges() : mAssigned(false) {}
1.67 + void Accumulate(const nsRect& aRect) {
1.68 + if (MOZ_LIKELY(mAssigned)) {
1.69 + x = std::min(x, aRect.X());
1.70 + xmost = std::max(xmost, aRect.XMost());
1.71 + } else {
1.72 + x = aRect.X();
1.73 + xmost = aRect.XMost();
1.74 + mAssigned = true;
1.75 + }
1.76 + }
1.77 + nscoord Width() { return xmost - x; }
1.78 + nscoord x;
1.79 + nscoord xmost;
1.80 + bool mAssigned;
1.81 + };
1.82 +
1.83 + struct InnerClipEdges {
1.84 + InnerClipEdges() : mAssignedLeft(false), mAssignedRight(false) {}
1.85 + void AccumulateLeft(const nsRect& aRect) {
1.86 + if (MOZ_LIKELY(mAssignedLeft)) {
1.87 + mLeft = std::max(mLeft, aRect.X());
1.88 + } else {
1.89 + mLeft = aRect.X();
1.90 + mAssignedLeft = true;
1.91 + }
1.92 + }
1.93 + void AccumulateRight(const nsRect& aRect) {
1.94 + if (MOZ_LIKELY(mAssignedRight)) {
1.95 + mRight = std::min(mRight, aRect.XMost());
1.96 + } else {
1.97 + mRight = aRect.XMost();
1.98 + mAssignedRight = true;
1.99 + }
1.100 + }
1.101 + nscoord mLeft;
1.102 + nscoord mRight;
1.103 + bool mAssignedLeft;
1.104 + bool mAssignedRight;
1.105 + };
1.106 +
1.107 + /**
1.108 + * Examines frames on the line to determine whether we should draw a left
1.109 + * and/or right marker, and if so, which frames should be completely hidden
1.110 + * and the bounds of what will be displayed between the markers.
1.111 + * @param aLine the line we're processing
1.112 + * @param aFramesToHide frames that should have their display items removed
1.113 + * @param aAlignmentEdges the outermost edges of all text and atomic
1.114 + * inline-level frames that are inside the area between the markers
1.115 + */
1.116 + void ExamineLineFrames(nsLineBox* aLine,
1.117 + FrameHashtable* aFramesToHide,
1.118 + AlignmentEdges* aAlignmentEdges);
1.119 +
1.120 + /**
1.121 + * LineHasOverflowingText calls this to analyze edges, both the block's
1.122 + * content edges and the hypothetical marker edges aligned at the block edges.
1.123 + * @param aFrame the descendant frame of mBlock that we're analyzing
1.124 + * @param aContentArea the block's content area
1.125 + * @param aInsideMarkersArea the rectangle between the markers
1.126 + * @param aFramesToHide frames that should have their display items removed
1.127 + * @param aAlignmentEdges the outermost edges of all text and atomic
1.128 + * inline-level frames that are inside the area between the markers
1.129 + * @param aFoundVisibleTextOrAtomic is set to true if a text or atomic
1.130 + * inline-level frame is visible between the marker edges
1.131 + * @param aClippedMarkerEdges the innermost edges of all text and atomic
1.132 + * inline-level frames that are clipped by the current marker width
1.133 + */
1.134 + void ExamineFrameSubtree(nsIFrame* aFrame,
1.135 + const nsRect& aContentArea,
1.136 + const nsRect& aInsideMarkersArea,
1.137 + FrameHashtable* aFramesToHide,
1.138 + AlignmentEdges* aAlignmentEdges,
1.139 + bool* aFoundVisibleTextOrAtomic,
1.140 + InnerClipEdges* aClippedMarkerEdges);
1.141 +
1.142 + /**
1.143 + * ExamineFrameSubtree calls this to analyze a frame against the hypothetical
1.144 + * marker edges (aInsideMarkersArea) for text frames and atomic inline-level
1.145 + * elements. A text frame adds its extent inside aInsideMarkersArea where
1.146 + * grapheme clusters are fully visible. An atomic adds its border box if
1.147 + * it's fully inside aInsideMarkersArea, otherwise the frame is added to
1.148 + * aFramesToHide.
1.149 + * @param aFrame the descendant frame of mBlock that we're analyzing
1.150 + * @param aFrameType aFrame's frame type
1.151 + * @param aInsideMarkersArea the rectangle between the markers
1.152 + * @param aFramesToHide frames that should have their display items removed
1.153 + * @param aAlignmentEdges the outermost edges of all text and atomic
1.154 + * inline-level frames that are inside the area between the markers
1.155 + * inside aInsideMarkersArea
1.156 + * @param aFoundVisibleTextOrAtomic is set to true if a text or atomic
1.157 + * inline-level frame is visible between the marker edges
1.158 + * @param aClippedMarkerEdges the innermost edges of all text and atomic
1.159 + * inline-level frames that are clipped by the current marker width
1.160 + */
1.161 + void AnalyzeMarkerEdges(nsIFrame* aFrame,
1.162 + const nsIAtom* aFrameType,
1.163 + const nsRect& aInsideMarkersArea,
1.164 + FrameHashtable* aFramesToHide,
1.165 + AlignmentEdges* aAlignmentEdges,
1.166 + bool* aFoundVisibleTextOrAtomic,
1.167 + InnerClipEdges* aClippedMarkerEdges);
1.168 +
1.169 + /**
1.170 + * Clip or remove items given the final marker edges. ("clip" here just means
1.171 + * assigning mLeftEdge/mRightEdge for any nsCharClipDisplayItem that needs it,
1.172 + * see nsDisplayList.h for a description of that item).
1.173 + * @param aFramesToHide remove display items for these frames
1.174 + * @param aInsideMarkersArea is the area inside the markers
1.175 + */
1.176 + void PruneDisplayListContents(nsDisplayList* aList,
1.177 + const FrameHashtable& aFramesToHide,
1.178 + const nsRect& aInsideMarkersArea);
1.179 +
1.180 + /**
1.181 + * ProcessLine calls this to create display items for the markers and insert
1.182 + * them into mMarkerList.
1.183 + * @param aLine the line we're processing
1.184 + * @param aCreateLeft if true, create a marker on the left side
1.185 + * @param aCreateRight if true, create a marker on the right side
1.186 + * @param aInsideMarkersArea is the area inside the markers
1.187 + */
1.188 + void CreateMarkers(const nsLineBox* aLine,
1.189 + bool aCreateLeft,
1.190 + bool aCreateRight,
1.191 + const nsRect& aInsideMarkersArea);
1.192 +
1.193 + nsRect mContentArea;
1.194 + nsDisplayListBuilder* mBuilder;
1.195 + nsIFrame* mBlock;
1.196 + nsIScrollableFrame* mScrollableFrame;
1.197 + nsDisplayList mMarkerList;
1.198 + bool mBlockIsRTL;
1.199 + bool mCanHaveHorizontalScrollbar;
1.200 + bool mAdjustForPixelSnapping;
1.201 +
1.202 + class Marker {
1.203 + public:
1.204 + void Init(const nsStyleTextOverflowSide& aStyle) {
1.205 + mInitialized = false;
1.206 + mWidth = 0;
1.207 + mStyle = &aStyle;
1.208 + }
1.209 +
1.210 + /**
1.211 + * Setup the marker string and calculate its size, if not done already.
1.212 + */
1.213 + void SetupString(nsIFrame* aFrame);
1.214 +
1.215 + bool IsNeeded() const {
1.216 + return mHasOverflow;
1.217 + }
1.218 + void Reset() {
1.219 + mHasOverflow = false;
1.220 + }
1.221 +
1.222 + // The current width of the marker, the range is [0 .. mIntrinsicWidth].
1.223 + nscoord mWidth;
1.224 + // The intrinsic width of the marker.
1.225 + nscoord mIntrinsicWidth;
1.226 + // The style for this side.
1.227 + const nsStyleTextOverflowSide* mStyle;
1.228 + // True if there is visible overflowing inline content on this side.
1.229 + bool mHasOverflow;
1.230 + // True if mMarkerString and mWidth have been setup from style.
1.231 + bool mInitialized;
1.232 + // True if the style is text-overflow:clip on this side and the marker
1.233 + // won't cause the line to become empty.
1.234 + bool mActive;
1.235 + };
1.236 +
1.237 + Marker mLeft; // the horizontal left marker
1.238 + Marker mRight; // the horizontal right marker
1.239 +};
1.240 +
1.241 +} // namespace css
1.242 +} // namespace mozilla
1.243 +
1.244 +#endif /* !defined(TextOverflow_h_) */
