void GlyphPageTreeNode::initializeOverridePage(const FontData* fontData, unsigned pageNumber)
{
GlyphPage* parentPage = m_parent->page();
// Get the pure page for the fallback font (at level 1 with no
// overrides). getRootChild will always create a page if one
// doesn't exist, but the page doesn't necessarily have glyphs
// (this pointer may be 0).
GlyphPage* fallbackPage = getNormalRootChild(fontData, pageNumber)->page();
if (!parentPage) {
// When the parent has no glyphs for this page, we can easily
// override it just by supplying the glyphs from our font.
m_page = fallbackPage;
return;
}
if (!fallbackPage) {
// When our font has no glyphs for this page, we can just reference the
// parent page.
m_page = parentPage;
return;
}
// Combine the parent's glyphs and ours to form a new more complete page.
m_page = GlyphPage::createForMixedFontData(this);
// Overlay the parent page on the fallback page. Check if the fallback font
// has added anything.
bool newGlyphs = false;
for (unsigned i = 0; i < GlyphPage::size; i++) {
if (parentPage->glyphAt(i)) {
m_page->setGlyphDataForIndex(i, parentPage->glyphDataForIndex(i));
} else if (fallbackPage->glyphAt(i)) {
m_page->setGlyphDataForIndex(i, fallbackPage->glyphDataForIndex(i));
newGlyphs = true;
}
if (parentPage->customFontToLoadAt(i)) {
m_page->setCustomFontToLoad(i, parentPage->customFontToLoadAt(i));
} else if (fallbackPage->customFontToLoadAt(i) && !parentPage->glyphAt(i)) {
m_page->setCustomFontToLoad(i, fallbackPage->customFontToLoadAt(i));
newGlyphs = true;
}
}
if (!newGlyphs) {
// We didn't override anything, so our override is just the parent page.
m_page = parentPage;
}
}
void GlyphPageTreeNode::initializePage(const FontData* fontData, unsigned pageNumber)
{
ASSERT(!m_page);
// This function must not be called for the root of the tree, because that
// level does not contain any glyphs.
ASSERT(m_level > 0 && m_parent);
// The parent's page will be 0 if we are level one or the parent's font data
// did not contain any glyphs for that page.
GlyphPage* parentPage = m_parent->page();
// NULL FontData means we're being asked for the system fallback font.
if (fontData) {
if (m_level == 1) {
// Children of the root hold pure pages. These will cover only one
// font data's glyphs, and will have glyph index 0 if the font data does not
// contain the glyph.
unsigned start = pageNumber * GlyphPage::size;
UChar buffer[GlyphPage::size * 2 + 2];
unsigned bufferLength;
unsigned i;
// Fill in a buffer with the entire "page" of characters that we want to look up glyphs for.
if (start < 0x10000) {
bufferLength = GlyphPage::size;
for (i = 0; i < GlyphPage::size; i++)
buffer[i] = start + i;
if (start == 0) {
// Control characters must not render at all.
for (i = 0; i < 0x20; ++i)
buffer[i] = zeroWidthSpace;
for (i = 0x7F; i < 0xA0; i++)
buffer[i] = zeroWidthSpace;
buffer[softHyphen] = zeroWidthSpace;
// \n, \t, and nonbreaking space must render as a space.
buffer[newlineCharacter] = space;
buffer[characterTabulation] = space;
buffer[noBreakSpace] = space;
} else if (start == (leftToRightMark & ~(GlyphPage::size - 1))) {
// LRM, RLM, LRE, RLE, ZWNJ, ZWJ, and PDF must not render at all.
buffer[leftToRightMark - start] = zeroWidthSpace;
buffer[rightToLeftMark - start] = zeroWidthSpace;
buffer[leftToRightEmbed - start] = zeroWidthSpace;
buffer[rightToLeftEmbed - start] = zeroWidthSpace;
buffer[leftToRightOverride - start] = zeroWidthSpace;
buffer[rightToLeftOverride - start] = zeroWidthSpace;
buffer[zeroWidthNonJoiner - start] = zeroWidthSpace;
buffer[zeroWidthJoiner - start] = zeroWidthSpace;
buffer[popDirectionalFormatting - start] = zeroWidthSpace;
} else if (start == (objectReplacementCharacter & ~(GlyphPage::size - 1))) {
// Object replacement character must not render at all.
buffer[objectReplacementCharacter - start] = zeroWidthSpace;
} else if (start == (zeroWidthNoBreakSpace & ~(GlyphPage::size - 1))) {
// ZWNBS/BOM must not render at all.
buffer[zeroWidthNoBreakSpace - start] = zeroWidthSpace;
}
} else {
bufferLength = GlyphPage::size * 2;
for (i = 0; i < GlyphPage::size; i++) {
int c = i + start;
buffer[i * 2] = U16_LEAD(c);
buffer[i * 2 + 1] = U16_TRAIL(c);
}
}
// Now that we have a buffer full of characters, we want to get back an array
// of glyph indices. This part involves calling into the platform-specific
// routine of our glyph map for actually filling in the page with the glyphs.
// Success is not guaranteed. For example, Times fails to fill page 260, giving glyph data
// for only 128 out of 256 characters.
bool haveGlyphs;
if (!fontData->isSegmented()) {
m_page = GlyphPage::createForSingleFontData(this, toSimpleFontData(fontData));
haveGlyphs = fill(m_page.get(), 0, GlyphPage::size, buffer, bufferLength, toSimpleFontData(fontData));
} else {
m_page = GlyphPage::createForMixedFontData(this);
haveGlyphs = false;
const SegmentedFontData* segmentedFontData = toSegmentedFontData(fontData);
for (int i = segmentedFontData->numRanges() - 1; i >= 0; i--) {
const FontDataRange& range = segmentedFontData->rangeAt(i);
// all this casting is to ensure all the parameters to min and max have the same type,
// to avoid ambiguous template parameter errors on Windows
int from = max(0, static_cast<int>(range.from()) - static_cast<int>(start));
int to = 1 + min(static_cast<int>(range.to()) - static_cast<int>(start), static_cast<int>(GlyphPage::size) - 1);
if (from >= static_cast<int>(GlyphPage::size) || to <= 0)
continue;
// If this is a custom font needs to be loaded, do not fill
// the page so that font fallback is used while loading.
RefPtr<CustomFontData> customData = range.fontData()->customFontData();
if (customData && customData->isLoadingFallback()) {
for (int j = from; j < to; j++) {
m_page->setCustomFontToLoad(j, customData.get());
haveGlyphs = true;
}
continue;
}
haveGlyphs |= fill(m_page.get(), from, to - from, buffer + from * (start < 0x10000 ? 1 : 2), (to - from) * (start < 0x10000 ? 1 : 2), range.fontData().get());
}
}
if (!haveGlyphs)
m_page = nullptr;
} else if (parentPage && parentPage->owner() != m_parent) {
// The page we're overriding may not be owned by our parent node.
// This happens when our parent node provides no useful overrides
// and just copies the pointer to an already-existing page (see
// below).
//
// We want our override to be shared by all nodes that reference
// that page to avoid duplication, and so standardize on having the
// page's owner collect all the overrides. Call getChild on the
// page owner with the desired font data (this will populate
// the page) and then reference it.
m_page = parentPage->owner()->getChild(fontData, pageNumber)->page();
} else {
// Get the pure page for the fallback font (at level 1 with no
// overrides). getRootChild will always create a page if one
// doesn't exist, but the page doesn't necessarily have glyphs
// (this pointer may be 0).
GlyphPage* fallbackPage = getRootChild(fontData, pageNumber)->page();
if (!parentPage) {
// When the parent has no glyphs for this page, we can easily
// override it just by supplying the glyphs from our font.
m_page = fallbackPage;
} else if (!fallbackPage) {
// When our font has no glyphs for this page, we can just reference the
// parent page.
m_page = parentPage;
} else {
// Combine the parent's glyphs and ours to form a new more complete page.
m_page = GlyphPage::createForMixedFontData(this);
// Overlay the parent page on the fallback page. Check if the fallback font
// has added anything.
bool newGlyphs = false;
for (unsigned i = 0; i < GlyphPage::size; i++) {
if (parentPage->glyphAt(i)) {
m_page->setGlyphDataForIndex(i, parentPage->glyphDataForIndex(i));
} else if (fallbackPage->glyphAt(i)) {
m_page->setGlyphDataForIndex(i, fallbackPage->glyphDataForIndex(i));
newGlyphs = true;
}
if (parentPage->customFontToLoadAt(i)) {
m_page->setCustomFontToLoad(i, parentPage->customFontToLoadAt(i));
} else if (fallbackPage->customFontToLoadAt(i) && !parentPage->glyphAt(i)) {
m_page->setCustomFontToLoad(i, fallbackPage->customFontToLoadAt(i));
newGlyphs = true;
}
}
if (!newGlyphs)
// We didn't override anything, so our override is just the parent page.
m_page = parentPage;
}
}
} else {
// System fallback. Initialized with the parent's page here, as individual
// entries may use different fonts depending on character. If the Font
// ever finds it needs a glyph out of the system fallback page, it will
// ask the system for the best font to use and fill that glyph in for us.
if (parentPage)
m_page = parentPage->createCopiedSystemFallbackPage(this);
else
m_page = GlyphPage::createForMixedFontData(this);
}
}