gecko/gfx/thebes/gfxDWriteFonts.cpp

427 lines
15 KiB
C++

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Foundation code.
*
* The Initial Developer of the Original Code is Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2010
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Bas Schouten <bschouten@mozilla.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "gfxDWriteFonts.h"
#include "gfxDWriteShaper.h"
#include "gfxHarfBuzzShaper.h"
#include "gfxDWriteFontList.h"
#include "gfxContext.h"
#include <dwrite.h>
#include "gfxDWriteTextAnalysis.h"
#include "harfbuzz/hb-blob.h"
// Chosen this as to resemble DWrite's own oblique face style.
#define OBLIQUE_SKEW_FACTOR 0.3
// This is also in gfxGDIFont.cpp. Would be nice to put it somewhere common,
// but we can't declare it in the gfxFont.h or gfxFontUtils.h headers
// because those are exported, and the cairo headers aren't.
static inline cairo_antialias_t
GetCairoAntialiasOption(gfxFont::AntialiasOption anAntialiasOption)
{
switch (anAntialiasOption) {
default:
case gfxFont::kAntialiasDefault:
return CAIRO_ANTIALIAS_DEFAULT;
case gfxFont::kAntialiasNone:
return CAIRO_ANTIALIAS_NONE;
case gfxFont::kAntialiasGrayscale:
return CAIRO_ANTIALIAS_GRAY;
case gfxFont::kAntialiasSubpixel:
return CAIRO_ANTIALIAS_SUBPIXEL;
}
}
////////////////////////////////////////////////////////////////////////////////
// gfxDWriteFont
gfxDWriteFont::gfxDWriteFont(gfxFontEntry *aFontEntry,
const gfxFontStyle *aFontStyle,
PRBool aNeedsBold,
AntialiasOption anAAOption)
: gfxFont(aFontEntry, aFontStyle, anAAOption)
, mCairoFontFace(nsnull)
, mCairoScaledFont(nsnull)
, mNeedsOblique(PR_FALSE)
, mNeedsBold(aNeedsBold)
{
gfxDWriteFontEntry *fe =
static_cast<gfxDWriteFontEntry*>(aFontEntry);
nsresult rv;
DWRITE_FONT_SIMULATIONS sims = DWRITE_FONT_SIMULATIONS_NONE;
if ((GetStyle()->style & (FONT_STYLE_ITALIC | FONT_STYLE_OBLIQUE)) &&
!fe->IsItalic()) {
// For this we always use the font_matrix for uniformity. Not the
// DWrite simulation.
mNeedsOblique = PR_TRUE;
}
PRInt8 baseWeight, weightDistance;
GetStyle()->ComputeWeightAndOffset(&baseWeight, &weightDistance);
if (aNeedsBold) {
sims |= DWRITE_FONT_SIMULATIONS_BOLD;
}
rv = fe->CreateFontFace(getter_AddRefs(mFontFace), sims);
if (NS_FAILED(rv)) {
mIsValid = PR_FALSE;
return;
}
ComputeMetrics();
if (FontCanSupportHarfBuzz()) {
mHarfBuzzShaper = new gfxHarfBuzzShaper(this);
}
}
gfxDWriteFont::~gfxDWriteFont()
{
if (mCairoFontFace) {
cairo_font_face_destroy(mCairoFontFace);
}
if (mCairoScaledFont) {
cairo_scaled_font_destroy(mCairoScaledFont);
}
}
gfxFont*
gfxDWriteFont::CopyWithAntialiasOption(AntialiasOption anAAOption)
{
return new gfxDWriteFont(static_cast<gfxDWriteFontEntry*>(mFontEntry.get()),
&mStyle, mNeedsBold, anAAOption);
}
void
gfxDWriteFont::CreatePlatformShaper()
{
mPlatformShaper = new gfxDWriteShaper(this);
}
nsString
gfxDWriteFont::GetUniqueName()
{
return mFontEntry->Name();
}
const gfxFont::Metrics&
gfxDWriteFont::GetMetrics()
{
return mMetrics;
}
void
gfxDWriteFont::ComputeMetrics()
{
DWRITE_FONT_METRICS fontMetrics;
mFontFace->GetMetrics(&fontMetrics);
if (mStyle.sizeAdjust != 0.0) {
gfxFloat aspect = (gfxFloat)fontMetrics.xHeight /
fontMetrics.designUnitsPerEm;
mAdjustedSize = mStyle.GetAdjustedSize(aspect);
} else {
mAdjustedSize = mStyle.size;
}
mMetrics.xHeight =
((gfxFloat)fontMetrics.xHeight /
fontMetrics.designUnitsPerEm) * mAdjustedSize;
mMetrics.maxAscent =
ceil(((gfxFloat)fontMetrics.ascent /
fontMetrics.designUnitsPerEm) * mAdjustedSize);
mMetrics.maxDescent =
ceil(((gfxFloat)fontMetrics.descent /
fontMetrics.designUnitsPerEm) * mAdjustedSize);
mMetrics.maxHeight = mMetrics.maxAscent + mMetrics.maxDescent;
mMetrics.emHeight = mAdjustedSize;
mMetrics.emAscent = mMetrics.emHeight *
mMetrics.maxAscent / mMetrics.maxHeight;
mMetrics.emDescent = mMetrics.emHeight - mMetrics.emAscent;
mMetrics.maxAdvance = mAdjustedSize;
// try to get the true maxAdvance value from 'hhea'
PRUint8 *tableData;
PRUint32 len;
void *tableContext = NULL;
BOOL exists;
HRESULT hr =
mFontFace->TryGetFontTable(DWRITE_MAKE_OPENTYPE_TAG('h', 'h', 'e', 'a'),
(const void**)&tableData,
&len,
&tableContext,
&exists);
if (SUCCEEDED(hr)) {
if (exists && len >= sizeof(mozilla::HheaTable)) {
const mozilla::HheaTable* hhea =
reinterpret_cast<const mozilla::HheaTable*>(tableData);
mMetrics.maxAdvance = ((gfxFloat)PRUint16(hhea->advanceWidthMax) /
fontMetrics.designUnitsPerEm) * mAdjustedSize;
}
mFontFace->ReleaseFontTable(tableContext);
}
mMetrics.internalLeading =
ceil(((gfxFloat)(fontMetrics.ascent +
fontMetrics.descent -
fontMetrics.designUnitsPerEm) /
fontMetrics.designUnitsPerEm) * mAdjustedSize);
mMetrics.externalLeading =
ceil(((gfxFloat)fontMetrics.lineGap /
fontMetrics.designUnitsPerEm) * mAdjustedSize);
UINT16 glyph = (PRUint16)GetSpaceGlyph();
DWRITE_GLYPH_METRICS metrics;
mFontFace->GetDesignGlyphMetrics(&glyph, 1, &metrics);
mMetrics.spaceWidth =
((gfxFloat)metrics.advanceWidth /
fontMetrics.designUnitsPerEm) * mAdjustedSize;
// try to get aveCharWidth from the OS/2 table, fall back to measuring 'x'
// if the table is not available
mMetrics.aveCharWidth = 0;
hr = mFontFace->TryGetFontTable(DWRITE_MAKE_OPENTYPE_TAG('O', 'S', '/', '2'),
(const void**)&tableData,
&len,
&tableContext,
&exists);
if (SUCCEEDED(hr)) {
if (exists && len >= 4) {
// Not checking against sizeof(mozilla::OS2Table) here because older
// versions of the table have different sizes; we only need the first
// two 16-bit fields here.
const mozilla::OS2Table* os2 =
reinterpret_cast<const mozilla::OS2Table*>(tableData);
mMetrics.aveCharWidth = ((gfxFloat)PRInt16(os2->xAvgCharWidth) /
fontMetrics.designUnitsPerEm) * mAdjustedSize;
}
mFontFace->ReleaseFontTable(tableContext);
}
UINT32 ucs;
if (mMetrics.aveCharWidth < 1) {
ucs = L'x';
if (SUCCEEDED(mFontFace->GetGlyphIndicesA(&ucs, 1, &glyph)) &&
SUCCEEDED(mFontFace->GetDesignGlyphMetrics(&glyph, 1, &metrics))) {
mMetrics.aveCharWidth =
((gfxFloat)metrics.advanceWidth /
fontMetrics.designUnitsPerEm) * mAdjustedSize;
} else {
// Let's just assume the X is square.
mMetrics.aveCharWidth =
((gfxFloat)fontMetrics.xHeight /
fontMetrics.designUnitsPerEm) * mAdjustedSize;
}
}
ucs = L'0';
if (SUCCEEDED(mFontFace->GetGlyphIndicesA(&ucs, 1, &glyph)) &&
SUCCEEDED(mFontFace->GetDesignGlyphMetrics(&glyph, 1, &metrics))) {
mMetrics.zeroOrAveCharWidth =
((gfxFloat)metrics.advanceWidth /
fontMetrics.designUnitsPerEm) * mAdjustedSize;
} else {
mMetrics.zeroOrAveCharWidth = mMetrics.aveCharWidth;
}
mMetrics.underlineOffset =
((gfxFloat)fontMetrics.underlinePosition /
fontMetrics.designUnitsPerEm) * mAdjustedSize;
mMetrics.underlineSize =
((gfxFloat)fontMetrics.underlineThickness /
fontMetrics.designUnitsPerEm) * mAdjustedSize;
mMetrics.strikeoutOffset =
((gfxFloat)fontMetrics.strikethroughPosition /
fontMetrics.designUnitsPerEm) * mAdjustedSize;
mMetrics.strikeoutSize =
((gfxFloat)fontMetrics.strikethroughThickness /
fontMetrics.designUnitsPerEm) * mAdjustedSize;
mMetrics.superscriptOffset = 0;
mMetrics.subscriptOffset = 0;
mFUnitsConvFactor = GetAdjustedSize() / fontMetrics.designUnitsPerEm;
SanitizeMetrics(&mMetrics, GetFontEntry()->mIsBadUnderlineFont);
#if 0
printf("Font: %p (%s) size: %f\n", this,
NS_ConvertUTF16toUTF8(GetName()).get(), mStyle.size);
printf(" emHeight: %f emAscent: %f emDescent: %f\n", mMetrics.emHeight, mMetrics.emAscent, mMetrics.emDescent);
printf(" maxAscent: %f maxDescent: %f maxAdvance: %f\n", mMetrics.maxAscent, mMetrics.maxDescent, mMetrics.maxAdvance);
printf(" internalLeading: %f externalLeading: %f\n", mMetrics.internalLeading, mMetrics.externalLeading);
printf(" spaceWidth: %f aveCharWidth: %f zeroOrAve: %f xHeight: %f\n",
mMetrics.spaceWidth, mMetrics.aveCharWidth, mMetrics.zeroOrAveCharWidth, mMetrics.xHeight);
printf(" uOff: %f uSize: %f stOff: %f stSize: %f supOff: %f subOff: %f\n",
mMetrics.underlineOffset, mMetrics.underlineSize, mMetrics.strikeoutOffset, mMetrics.strikeoutSize,
mMetrics.superscriptOffset, mMetrics.subscriptOffset);
#endif
}
PRUint32
gfxDWriteFont::GetSpaceGlyph()
{
UINT32 ucs = L' ';
UINT16 glyph;
HRESULT hr;
hr = mFontFace->GetGlyphIndicesA(&ucs, 1, &glyph);
if (FAILED(hr)) {
return 0;
}
return glyph;
}
PRBool
gfxDWriteFont::SetupCairoFont(gfxContext *aContext)
{
cairo_scaled_font_t *scaledFont = CairoScaledFont();
if (cairo_scaled_font_status(scaledFont) != CAIRO_STATUS_SUCCESS) {
// Don't cairo_set_scaled_font as that would propagate the error to
// the cairo_t, precluding any further drawing.
return PR_FALSE;
}
cairo_set_scaled_font(aContext->GetCairo(), scaledFont);
return PR_TRUE;
}
cairo_font_face_t *
gfxDWriteFont::CairoFontFace()
{
if (!mCairoFontFace) {
#ifdef CAIRO_HAS_DWRITE_FONT
mCairoFontFace =
cairo_dwrite_font_face_create_for_dwrite_fontface(
((gfxDWriteFontEntry*)mFontEntry.get())->mFont, mFontFace);
#endif
}
return mCairoFontFace;
}
cairo_scaled_font_t *
gfxDWriteFont::CairoScaledFont()
{
if (!mCairoScaledFont) {
cairo_matrix_t sizeMatrix;
cairo_matrix_t identityMatrix;
cairo_matrix_init_scale(&sizeMatrix, mAdjustedSize, mAdjustedSize);
cairo_matrix_init_identity(&identityMatrix);
cairo_font_options_t *fontOptions = cairo_font_options_create();
if (mNeedsOblique) {
double skewfactor = OBLIQUE_SKEW_FACTOR;
cairo_matrix_t style;
cairo_matrix_init(&style,
1, //xx
0, //yx
-1 * skewfactor, //xy
1, //yy
0, //x0
0); //y0
cairo_matrix_multiply(&sizeMatrix, &sizeMatrix, &style);
}
if (mAntialiasOption != kAntialiasDefault) {
cairo_font_options_set_antialias(fontOptions,
GetCairoAntialiasOption(mAntialiasOption));
}
mCairoScaledFont = cairo_scaled_font_create(CairoFontFace(),
&sizeMatrix,
&identityMatrix,
fontOptions);
cairo_font_options_destroy(fontOptions);
}
NS_ASSERTION(mAdjustedSize == 0.0 ||
cairo_scaled_font_status(mCairoScaledFont)
== CAIRO_STATUS_SUCCESS,
"Failed to make scaled font");
return mCairoScaledFont;
}
// Access to font tables packaged in hb_blob_t form
// object attached to the Harfbuzz blob, used to release
// the table when the blob is destroyed
class FontTableRec {
public:
FontTableRec(IDWriteFontFace *aFontFace, void *aContext)
: mFontFace(aFontFace), mContext(aContext)
{ }
~FontTableRec() {
mFontFace->ReleaseFontTable(mContext);
}
private:
IDWriteFontFace *mFontFace;
void *mContext;
};
/*static*/ void
gfxDWriteFont::DestroyBlobFunc(void* aUserData)
{
FontTableRec *ftr = static_cast<FontTableRec*>(aUserData);
delete ftr;
}
hb_blob_t *
gfxDWriteFont::GetFontTable(PRUint32 aTag)
{
const void *data;
UINT32 size;
void *context;
BOOL exists;
HRESULT hr = mFontFace->TryGetFontTable(NS_SWAP32(aTag),
&data, &size, &context, &exists);
if (SUCCEEDED(hr) && exists) {
FontTableRec *ftr = new FontTableRec(mFontFace, context);
return hb_blob_create(static_cast<const char*>(data), size,
HB_MEMORY_MODE_READONLY,
DestroyBlobFunc, ftr);
}
return nsnull;
}