bool SVGFontData::fillSVGGlyphPage(GlyphPage* pageToFill, unsigned offset, unsigned length, UChar* buffer, unsigned bufferLength, const SimpleFontData* fontData) const
{
ASSERT(fontData->isCustomFont());
ASSERT(fontData->isSVGFont());
SVGFontFaceElement* fontFaceElement = this->svgFontFaceElement();
ASSERT(fontFaceElement);
SVGFontElement* fontElement = fontFaceElement->associatedFontElement();
ASSERT(fontElement);
if (bufferLength == length)
return fillBMPGlyphs(fontElement, pageToFill, offset, length, buffer, fontData);
ASSERT(bufferLength == 2 * length);
return fillNonBMPGlyphs(fontElement, pageToFill, offset, length, buffer, fontData);
}
// We're supposed to return true if there are any glyphs in the range
// specified by |offset| and |length| in our font,
// false if there are none.
bool GlyphPage::fill(unsigned offset, unsigned length, UChar* characterBuffer,
unsigned bufferLength, const SimpleFontData* fontData)
{
// We have to handle BMP and non-BMP characters differently.
// FIXME: Add assertions to make sure that buffer is entirely in BMP
// or entirely in non-BMP.
if (bufferLength == length)
return fillBMPGlyphs(offset, length, characterBuffer, this, fontData, true);
if (bufferLength == 2 * length) {
// A non-BMP input buffer will be twice as long as output glyph buffer
// because each character in the non-BMP input buffer will be
// represented by a surrogate pair (two UChar's).
return fillNonBMPGlyphs(offset, length, characterBuffer, this, fontData);
}
ASSERT_NOT_REACHED();
return false;
}
// Fills |length| glyphs starting at |offset| in a |page| in the Basic
// Multilingual Plane (<= U+FFFF). The input buffer size should be the
// same as |length|. We can use the standard Windows GDI functions here.
// Returns true if any glyphs were found.
static bool fillBMPGlyphs(unsigned offset,
unsigned length,
UChar* buffer,
GlyphPage* page,
const SimpleFontData* fontData,
bool recurse)
{
HDC dc = GetDC((HWND)0);
HGDIOBJ oldFont = SelectObject(dc, fontData->platformData().hfont());
TEXTMETRIC tm = {0};
if (!GetTextMetrics(dc, &tm)) {
SelectObject(dc, oldFont);
ReleaseDC(0, dc);
if (recurse) {
if (PlatformBridge::ensureFontLoaded(fontData->platformData().hfont()))
return fillBMPGlyphs(offset, length, buffer, page, fontData, false);
fillEmptyGlyphs(page);
return false;
} else {
// FIXME: Handle gracefully the error if this call also fails.
// See http://crbug.com/6401
LOG_ERROR("Unable to get the text metrics after second attempt");
fillEmptyGlyphs(page);
return false;
}
}
// FIXME: GetGlyphIndices() sets each item of localGlyphBuffer[]
// with the one of the values listed below.
// * With the GGI_MARK_NONEXISTING_GLYPHS flag
// + If the font has a glyph available for the character,
// localGlyphBuffer[i] > 0x0.
// + If the font does not have glyphs available for the character,
// localGlyphBuffer[i] = 0x1F (TrueType Collection?) or
// 0xFFFF (OpenType?).
// * Without the GGI_MARK_NONEXISTING_GLYPHS flag
// + If the font has a glyph available for the character,
// localGlyphBuffer[i] > 0x0.
// + If the font does not have glyphs available for the character,
// localGlyphBuffer[i] = 0x80.
// (Windows automatically assigns the glyph for a box character to
// prevent ExtTextOut() from returning errors.)
// To avoid from hurting the rendering performance, this code just
// tells WebKit whether or not the all glyph indices for the given
// characters are 0x80 (i.e. a possibly-invalid glyph) and let it
// use alternative fonts for the characters.
// Although this may cause a problem, it seems to work fine as far as I
// have tested. (Obviously, I need more tests.)
WORD localGlyphBuffer[GlyphPage::size];
// FIXME: I find some Chinese characters can not be correctly displayed
// when call GetGlyphIndices without flag GGI_MARK_NONEXISTING_GLYPHS,
// because the corresponding glyph index is set as 0x20 when current font
// does not have glyphs available for the character. According a blog post
// http://blogs.msdn.com/michkap/archive/2006/06/28/649791.aspx
// I think we should switch to the way about calling GetGlyphIndices with
// flag GGI_MARK_NONEXISTING_GLYPHS, it should be OK according the
// description of MSDN.
// Also according to Jungshik and Hironori's suggestion and modification
// we treat turetype and raster Font as different way when windows version
// is less than Vista.
GetGlyphIndices(dc, buffer, length, localGlyphBuffer, GGI_MARK_NONEXISTING_GLYPHS);
// Copy the output to the GlyphPage
bool haveGlyphs = false;
int invalidGlyph = 0xFFFF;
const DWORD cffTableTag = 0x20464643; // 4-byte identifier for OpenType CFF table ('CFF ').
if (!isVistaOrNewer() && !(tm.tmPitchAndFamily & TMPF_TRUETYPE) && (GetFontData(dc, cffTableTag, 0, 0, 0) == GDI_ERROR))
invalidGlyph = 0x1F;
Glyph spaceGlyph = 0; // Glyph for a space. Lazily filled.
for (unsigned i = 0; i < length; i++) {
UChar c = buffer[i];
Glyph glyph = localGlyphBuffer[i];
const SimpleFontData* glyphFontData = fontData;
// When this character should be a space, we ignore whatever the font
// says and use a space. Otherwise, if fonts don't map one of these
// space or zero width glyphs, we will get a box.
if (Font::treatAsSpace(c)) {
// Hard code the glyph indices for characters that should be
// treated like spaces.
glyph = initSpaceGlyph(dc, &spaceGlyph);
} else if (glyph == invalidGlyph) {
// WebKit expects both the glyph index and FontData
// pointer to be 0 if the glyph is not present
glyph = 0;
glyphFontData = 0;
} else
haveGlyphs = true;
page->setGlyphDataForCharacter(offset + i, glyph, glyphFontData);
}
SelectObject(dc, oldFont);
ReleaseDC(0, dc);
return haveGlyphs;
}
