void setGlyphXPositions(bool isRTL)
{
double position = 0;
// logClustersIndex indexes logClusters for the first (or last when
// RTL) codepoint of the current glyph. Each time we advance a glyph,
// we skip over all the codepoints that contributed to the current
// glyph.
unsigned logClustersIndex = isRTL ? m_item.num_glyphs - 1 : 0;
for (int iter = 0; iter < m_item.num_glyphs; ++iter) {
// Glyphs are stored in logical order, but for layout purposes we
// always go left to right.
int i = isRTL ? m_item.num_glyphs - iter - 1 : iter;
m_glyphs16[i] = m_item.glyphs[i];
double offsetX = truncateFixedPointToInteger(m_item.offsets[i].x);
m_xPositions[i] = m_offsetX + position + offsetX;
double advance = truncateFixedPointToInteger(m_item.advances[i]);
// The first half of the conjuction works around the case where
// output glyphs aren't associated with any codepoints by the
// clusters log.
if (logClustersIndex < m_item.item.length
&& isWordBreak(m_item.item.pos + logClustersIndex, isRTL)) {
advance += m_wordSpacingAdjustment;
if (m_padding > 0) {
unsigned toPad = roundf(m_padPerWordBreak + m_padError);
m_padError += m_padPerWordBreak - toPad;
if (m_padding < toPad)
toPad = m_padding;
m_padding -= toPad;
advance += toPad;
}
}
// We would like to add m_letterSpacing after each cluster, but I
// don't know where the cluster information is. This is typically
// fine for Roman languages, but breaks more complex languages
// terribly.
// advance += m_letterSpacing;
if (isRTL) {
while (logClustersIndex > 0 && logClusters()[logClustersIndex] == i)
logClustersIndex--;
} else {
while (logClustersIndex < m_item.item.length && logClusters()[logClustersIndex] == i)
logClustersIndex++;
}
position += advance;
}
m_pixelWidth = position;
m_offsetX += m_pixelWidth;
}
// Return the rectangle for selecting the given range of code-points in the TextRun.
FloatRect Font::selectionRectForComplexText(const TextRun& run,
const FloatPoint& point, int height,
int from, int to) const
{
int fromX = -1, toX = -1;
ComplexTextController controller(run, 0, 0, this);
controller.setWordSpacingAdjustment(wordSpacing());
controller.setLetterSpacingAdjustment(letterSpacing());
controller.setPadding(run.expansion());
if (run.rtl()) {
// See FIXME in drawComplexText.
controller.reset(controller.widthOfFullRun());
controller.setPadding(run.expansion());
}
// Iterate through the script runs in logical order, searching for the run covering the positions of interest.
while (controller.nextScriptRun() && (fromX == -1 || toX == -1)) {
if (fromX == -1 && from >= 0 && static_cast<unsigned>(from) < controller.numCodePoints()) {
// |from| is within this script run. So we index the clusters log to
// find which glyph this code-point contributed to and find its x
// position.
int glyph = controller.logClusters()[from];
fromX = controller.positions()[glyph].x();
if (controller.rtl())
fromX += truncateFixedPointToInteger(controller.advances()[glyph]);
} else
from -= controller.numCodePoints();
if (toX == -1 && to >= 0 && static_cast<unsigned>(to) < controller.numCodePoints()) {
int glyph = controller.logClusters()[to];
toX = controller.positions()[glyph].x();
if (controller.rtl())
toX += truncateFixedPointToInteger(controller.advances()[glyph]);
} else
to -= controller.numCodePoints();
}
// The position in question might be just after the text.
if (fromX == -1)
fromX = controller.offsetX();
if (toX == -1)
toX = controller.offsetX();
ASSERT(fromX != -1 && toX != -1);
if (fromX < toX)
return FloatRect(point.x() + fromX, point.y(), toX - fromX, height);
return FloatRect(point.x() + toX, point.y(), fromX - toX, height);
}
static int glyphIndexForXPositionInScriptRun(const TextRunWalker& walker, int x)
{
const HB_Fixed* advances = walker.advances();
int glyphIndex;
if (walker.rtl()) {
for (glyphIndex = walker.length() - 1; glyphIndex >= 0; --glyphIndex) {
if (x < truncateFixedPointToInteger(advances[glyphIndex]))
break;
x -= truncateFixedPointToInteger(advances[glyphIndex]);
}
} else {
for (glyphIndex = 0; glyphIndex < walker.length(); ++glyphIndex) {
if (x < truncateFixedPointToInteger(advances[glyphIndex]))
break;
x -= truncateFixedPointToInteger(advances[glyphIndex]);
}
}
return glyphIndex;
}
void ComplexTextController::setGlyphPositions(bool isRTL)
{
const double rtlFlip = isRTL ? -1 : 1;
double position = 0;
// logClustersIndex indexes logClusters for the first codepoint of the current glyph.
// Each time we advance a glyph, we skip over all the codepoints that contributed to the current glyph.
int logClustersIndex = 0;
// Iterate through the glyphs in logical order, flipping for RTL where necessary.
// Glyphs are positioned starting from m_offsetX; in RTL mode they go leftwards from there.
for (size_t i = 0; i < m_item.num_glyphs; ++i) {
while (static_cast<unsigned>(logClustersIndex) < m_item.item.length && m_item.log_clusters[logClustersIndex] < i)
logClustersIndex++;
// If the current glyph is just after a space, add in the word spacing.
position += determineWordBreakSpacing(logClustersIndex);
m_glyphs16[i] = m_item.glyphs[i];
double offsetX = truncateFixedPointToInteger(m_item.offsets[i].x);
double offsetY = truncateFixedPointToInteger(m_item.offsets[i].y);
double advance = truncateFixedPointToInteger(m_item.advances[i]);
if (isRTL)
offsetX -= advance;
m_positions[i].set(m_offsetX + (position * rtlFlip) + offsetX,
m_startingY + offsetY);
if (m_currentFontData->isZeroWidthSpaceGlyph(m_glyphs16[i]))
continue;
// At the end of each cluster, add in the letter spacing.
if (i + 1 == m_item.num_glyphs || m_item.attributes[i + 1].clusterStart)
position += m_letterSpacing;
position += advance;
}
m_pixelWidth = std::max(position, 0.0);
m_offsetX += m_pixelWidth * rtlFlip;
}
FloatRect ComplexTextController::selectionRect(const FloatPoint& point, int height, int from, int to)
{
int fromX = -1, toX = -1;
// Iterate through the script runs in logical order, searching for the run covering the positions of interest.
while (nextScriptRun() && (fromX == -1 || toX == -1)) {
if (fromX == -1 && from >= 0 && static_cast<unsigned>(from) < numCodePoints()) {
// |from| is within this script run. So we index the clusters log to
// find which glyph this code-point contributed to and find its x
// position.
int glyph = m_item.log_clusters[from];
fromX = positions()[glyph].x();
if (rtl())
fromX += truncateFixedPointToInteger(m_item.advances[glyph]);
} else
from -= numCodePoints();
if (toX == -1 && to >= 0 && static_cast<unsigned>(to) < numCodePoints()) {
int glyph = m_item.log_clusters[to];
toX = positions()[glyph].x();
if (rtl())
toX += truncateFixedPointToInteger(m_item.advances[glyph]);
} else
to -= numCodePoints();
}
// The position in question might be just after the text.
if (fromX == -1)
fromX = offsetX();
if (toX == -1)
toX = offsetX();
ASSERT(fromX != -1 && toX != -1);
if (fromX < toX)
return FloatRect(point.x() + fromX, point.y(), toX - fromX, height);
return FloatRect(point.x() + toX, point.y(), fromX - toX, height);
}
static int glyphIndexForXPositionInScriptRun(const ComplexTextController& controller, int targetX)
{
// Iterate through the glyphs in logical order, seeing whether targetX falls between the previous
// position and halfway through the current glyph.
// FIXME: this code probably belongs in ComplexTextController.
int lastX = controller.offsetX() - (controller.rtl() ? -controller.width() : controller.width());
for (int glyphIndex = 0; static_cast<unsigned>(glyphIndex) < controller.length(); ++glyphIndex) {
int advance = truncateFixedPointToInteger(controller.advances()[glyphIndex]);
int nextX = static_cast<int>(controller.positions()[glyphIndex].x()) + advance / 2;
if (std::min(nextX, lastX) <= targetX && targetX <= std::max(nextX, lastX))
return glyphIndex;
lastX = nextX;
}
return controller.length() - 1;
}
void setGlyphXPositions(bool isRTL)
{
m_pixelWidth = 0;
for (unsigned i = 0; i < m_item.num_glyphs; ++i) {
int index;
if (isRTL)
index = m_item.num_glyphs - (i + 1);
else
index = i;
m_glyphs16[i] = m_item.glyphs[i];
m_xPositions[index] = m_offsetX + m_pixelWidth;
m_pixelWidth += truncateFixedPointToInteger(m_item.advances[index]);
}
m_offsetX += m_pixelWidth;
}
// Return the rectangle for selecting the given range of code-points in the TextRun.
FloatRect Font::selectionRectForComplexText(const TextRun& run,
const IntPoint& point, int height,
int from, int to) const
{
int fromX = -1, toX = -1, fromAdvance = -1, toAdvance = -1;
TextRunWalker walker(run, 0, this);
// Base will point to the x offset for the current script run. Note that, in
// the LTR case, width will be 0.
int base = walker.rtl() ? walker.widthOfFullRun() : 0;
const int leftEdge = base;
// We want to enumerate the script runs in code point order in the following
// code. This call also resets |walker|.
walker.setBackwardsIteration(false);
while (walker.nextScriptRun() && (fromX == -1 || toX == -1)) {
// TextRunWalker will helpfully accululate the x offsets for different
// script runs for us. For this code, however, we always want the x offsets
// to start from zero so we call this before each script run.
walker.setXOffsetToZero();
if (walker.rtl())
base -= walker.width();
if (fromX == -1 && from < walker.numCodePoints()) {
// |from| is within this script run. So we index the clusters log to
// find which glyph this code-point contributed to and find its x
// position.
int glyph = walker.logClusters()[from];
fromX = base + walker.xPositions()[glyph];
fromAdvance = walker.advances()[glyph];
} else
from -= walker.numCodePoints();
if (toX == -1 && to < walker.numCodePoints()) {
int glyph = walker.logClusters()[to];
toX = base + walker.xPositions()[glyph];
toAdvance = walker.advances()[glyph];
} else
to -= walker.numCodePoints();
if (!walker.rtl())
base += walker.width();
}
// The position in question might be just after the text.
const int rightEdge = base;
if (fromX == -1 && !from)
fromX = leftEdge;
else if (walker.rtl())
fromX += truncateFixedPointToInteger(fromAdvance);
if (toX == -1 && !to)
toX = rightEdge;
else if (!walker.rtl())
toX += truncateFixedPointToInteger(toAdvance);
ASSERT(fromX != -1 && toX != -1);
if (fromX < toX)
return FloatRect(point.x() + fromX, point.y(), toX - fromX, height);
return FloatRect(point.x() + toX, point.y(), fromX - toX, height);
}
