Source/core/platform/graphics/mac/SimpleFontDataMac.mm

/*
 * Copyright (C) 2005, 2006, 2010, 2011 Apple Inc. All rights reserved.
 * Copyright (C) 2006 Alexey Proskuryakov
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#import "config.h"
#import "core/platform/graphics/SimpleFontData.h"

#import <AppKit/AppKit.h>
#import <ApplicationServices/ApplicationServices.h>
#import <float.h>
#import <unicode/uchar.h>
#import "core/platform/SharedBuffer.h"
#import "core/platform/graphics/Color.h"
#import "core/platform/graphics/FloatRect.h"
#import "core/platform/graphics/Font.h"
#import "core/platform/graphics/FontCache.h"
#import "core/platform/graphics/FontDescription.h"
#import "core/platform/mac/BlockExceptions.h"
#import <wtf/Assertions.h>
#import <wtf/RetainPtr.h>
#import <wtf/StdLibExtras.h>
#import <wtf/UnusedParam.h>

@interface NSFont (WebAppKitSecretAPI)
- (BOOL)_isFakeFixedPitch;
@end

// The names of these constants were taken from history
// /trunk/WebKit/WebCoreSupport.subproj/WebTextRenderer.m@9311. The values
// were derived from the assembly of libWebKitSystemInterfaceLeopard.a.
enum CGFontRenderingMode {
  kCGFontRenderingMode1BitPixelAligned = 0x0,
  kCGFontRenderingModeAntialiasedPixelAligned = 0x1,
  kCGFontRenderingModeAntialiased = 0xd
};

// Forward declare Mac SPIs.
extern "C" {
// Request for public API: rdar://13803586
bool CGFontGetGlyphAdvancesForStyle(CGFontRef font, CGAffineTransform* transform, CGFontRenderingMode renderingMode, ATSGlyphRef* glyph, size_t count, CGSize* advance);

// Request for public API: rdar://13803619
CTLineRef CTLineCreateWithUniCharProvider(const UniChar* (*provide)(CFIndex stringIndex, CFIndex* charCount, CFDictionaryRef* attributes, void* context), void (*dispose)(const UniChar* chars, void* context), void* context);
}

static CGFontRenderingMode cgFontRenderingModeForNSFont(NSFont* font) {
    if (!font)
        return kCGFontRenderingModeAntialiasedPixelAligned;

    switch ([font renderingMode]) {
        case NSFontIntegerAdvancementsRenderingMode: return kCGFontRenderingMode1BitPixelAligned;
        case NSFontAntialiasedIntegerAdvancementsRenderingMode: return kCGFontRenderingModeAntialiasedPixelAligned;
        default: return kCGFontRenderingModeAntialiased;
    }
}

using namespace std;

namespace WebCore {

static bool fontHasVerticalGlyphs(CTFontRef ctFont)
{
    // The check doesn't look neat but this is what AppKit does for vertical writing...
    RetainPtr<CFArrayRef> tableTags(AdoptCF, CTFontCopyAvailableTables(ctFont, kCTFontTableOptionNoOptions));
    CFIndex numTables = CFArrayGetCount(tableTags.get());
    for (CFIndex index = 0; index < numTables; ++index) {
        CTFontTableTag tag = (CTFontTableTag)(uintptr_t)CFArrayGetValueAtIndex(tableTags.get(), index);
        if (tag == kCTFontTableVhea || tag == kCTFontTableVORG)
            return true;
    }
    return false;
}

static bool initFontData(SimpleFontData* fontData)
{
    if (!fontData->platformData().cgFont())
        return false;

    return true;
}

static NSString *webFallbackFontFamily(void)
{
    DEFINE_STATIC_LOCAL(RetainPtr<NSString>, webFallbackFontFamily, ([[NSFont systemFontOfSize:16.0f] familyName]));
    return webFallbackFontFamily.get();
}

const SimpleFontData* SimpleFontData::getCompositeFontReferenceFontData(NSFont *key) const
{
    if (key && !CFEqual(RetainPtr<CFStringRef>(AdoptCF, CTFontCopyPostScriptName(CTFontRef(key))).get(), CFSTR("LastResort"))) {
        if (!m_derivedFontData)
            m_derivedFontData = DerivedFontData::create(isCustomFont());
        if (!m_derivedFontData->compositeFontReferences)
            m_derivedFontData->compositeFontReferences.adoptCF(CFDictionaryCreateMutable(kCFAllocatorDefault, 1, &kCFTypeDictionaryKeyCallBacks, NULL));
        else {
            const SimpleFontData* found = static_cast<const SimpleFontData*>(CFDictionaryGetValue(m_derivedFontData->compositeFontReferences.get(), static_cast<const void *>(key)));
            if (found)
                return found;
        }
        if (CFMutableDictionaryRef dictionary = m_derivedFontData->compositeFontReferences.get()) {
            bool isUsingPrinterFont = platformData().isPrinterFont();
            NSFont *substituteFont = isUsingPrinterFont ? [key printerFont] : [key screenFont];

            CTFontSymbolicTraits traits = CTFontGetSymbolicTraits(toCTFontRef(substituteFont));
            bool syntheticBold = platformData().syntheticBold() && !(traits & kCTFontBoldTrait);
            bool syntheticOblique = platformData().syntheticOblique() && !(traits & kCTFontItalicTrait);

            FontPlatformData substitutePlatform(substituteFont, platformData().size(), isUsingPrinterFont, syntheticBold, syntheticOblique, platformData().orientation(), platformData().widthVariant());
            SimpleFontData* value = new SimpleFontData(substitutePlatform, isCustomFont());
            if (value) {
                CFDictionaryAddValue(dictionary, key, value);
                return value;
            }
        }
    }
    return 0;
}

void SimpleFontData::platformInit()
{
    m_syntheticBoldOffset = m_platformData.m_syntheticBold ? 1.0f : 0.f;

    bool failedSetup = false;
    if (!initFontData(this)) {
        // Ack! Something very bad happened, like a corrupt font.
        // Try looking for an alternate 'base' font for this renderer.

        // Special case hack to use "Times New Roman" in place of "Times".
        // "Times RO" is a common font whose family name is "Times".
        // It overrides the normal "Times" family font.
        // It also appears to have a corrupt regular variant.
        NSString *fallbackFontFamily;
        if ([[m_platformData.font() familyName] isEqual:@"Times"])
            fallbackFontFamily = @"Times New Roman";
        else
            fallbackFontFamily = webFallbackFontFamily();
        
        // Try setting up the alternate font.
        // This is a last ditch effort to use a substitute font when something has gone wrong.
#if !ERROR_DISABLED
        RetainPtr<NSFont> initialFont = m_platformData.font();
#endif
        if (m_platformData.font())
            m_platformData.setFont([[NSFontManager sharedFontManager] convertFont:m_platformData.font() toFamily:fallbackFontFamily]);
        else
            m_platformData.setFont([NSFont fontWithName:fallbackFontFamily size:m_platformData.size()]);

        if (!initFontData(this)) {
            if ([fallbackFontFamily isEqual:@"Times New Roman"]) {
                // OK, couldn't setup Times New Roman as an alternate to Times, fallback
                // on the system font.  If this fails we have no alternative left.
                m_platformData.setFont([[NSFontManager sharedFontManager] convertFont:m_platformData.font() toFamily:webFallbackFontFamily()]);
                if (!initFontData(this)) {
                    // We tried, Times, Times New Roman, and the system font. No joy. We have to give up.
                    LOG_ERROR("unable to initialize with font %@", initialFont.get());
                    failedSetup = true;
                }
            } else {
                // We tried the requested font and the system font. No joy. We have to give up.
                LOG_ERROR("unable to initialize with font %@", initialFont.get());
                failedSetup = true;
            }
        }

        // Report the problem.
        LOG_ERROR("Corrupt font detected, using %@ in place of %@.",
            [m_platformData.font() familyName], [initialFont.get() familyName]);
    }

    // If all else fails, try to set up using the system font.
    // This is probably because Times and Times New Roman are both unavailable.
    if (failedSetup) {
        m_platformData.setFont([NSFont systemFontOfSize:[m_platformData.font() pointSize]]);
        LOG_ERROR("failed to set up font, using system font %s", m_platformData.font());
        initFontData(this);
    }
    
    int iAscent;
    int iDescent;
    int iLineGap;
    unsigned unitsPerEm;
    iAscent = CGFontGetAscent(m_platformData.cgFont());
    // Some fonts erroneously specify a positive descender value. We follow Core Text in assuming that
    // such fonts meant the same distance, but in the reverse direction.
    iDescent = -abs(CGFontGetDescent(m_platformData.cgFont()));
    iLineGap = CGFontGetLeading(m_platformData.cgFont());
    unitsPerEm = CGFontGetUnitsPerEm(m_platformData.cgFont());

    float pointSize = m_platformData.m_size;
    float ascent = scaleEmToUnits(iAscent, unitsPerEm) * pointSize;
    float descent = -scaleEmToUnits(iDescent, unitsPerEm) * pointSize;
    float lineGap = scaleEmToUnits(iLineGap, unitsPerEm) * pointSize;

    // We need to adjust Times, Helvetica, and Courier to closely match the
    // vertical metrics of their Microsoft counterparts that are the de facto
    // web standard. The AppKit adjustment of 20% is too big and is
    // incorrectly added to line spacing, so we use a 15% adjustment instead
    // and add it to the ascent.
    NSString *familyName = [m_platformData.font() familyName];
    if ([familyName isEqualToString:@"Times"] || [familyName isEqualToString:@"Helvetica"] || [familyName isEqualToString:@"Courier"])
        ascent += floorf(((ascent + descent) * 0.15f) + 0.5f);

    // Compute and store line spacing, before the line metrics hacks are applied.
    m_fontMetrics.setLineSpacing(lroundf(ascent) + lroundf(descent) + lroundf(lineGap));

    // Hack Hiragino line metrics to allow room for marked text underlines.
    // <rdar://problem/5386183>
    if (descent < 3 && lineGap >= 3 && [familyName hasPrefix:@"Hiragino"]) {
        lineGap -= 3 - descent;
        descent = 3;
    }
    
    if (platformData().orientation() == Vertical && !isTextOrientationFallback())
        m_hasVerticalGlyphs = fontHasVerticalGlyphs(m_platformData.ctFont());

    float xHeight;

    if (platformData().orientation() == Horizontal) {
        // Measure the actual character "x", since it's possible for it to extend below the baseline, and we need the
        // reported x-height to only include the portion of the glyph that is above the baseline.
        GlyphPage* glyphPageZero = GlyphPageTreeNode::getRootChild(this, 0)->page();
        NSGlyph xGlyph = glyphPageZero ? glyphPageZero->glyphDataForCharacter('x').glyph : 0;
        if (xGlyph)
            xHeight = -CGRectGetMinY(platformBoundsForGlyph(xGlyph));
        else
            xHeight = scaleEmToUnits(CGFontGetXHeight(m_platformData.cgFont()), unitsPerEm) * pointSize;
    } else
        xHeight = verticalRightOrientationFontData()->fontMetrics().xHeight();

    m_fontMetrics.setUnitsPerEm(unitsPerEm);
    m_fontMetrics.setAscent(ascent);
    m_fontMetrics.setDescent(descent);
    m_fontMetrics.setLineGap(lineGap);
    m_fontMetrics.setXHeight(xHeight);
}

static CFDataRef copyFontTableForTag(FontPlatformData& platformData, FourCharCode tableName)
{
    return CGFontCopyTableForTag(platformData.cgFont(), tableName);
}

void SimpleFontData::platformCharWidthInit()
{
    m_avgCharWidth = 0;
    m_maxCharWidth = 0;
    
    RetainPtr<CFDataRef> os2Table(AdoptCF, copyFontTableForTag(m_platformData, 'OS/2'));
    if (os2Table && CFDataGetLength(os2Table.get()) >= 4) {
        const UInt8* os2 = CFDataGetBytePtr(os2Table.get());
        SInt16 os2AvgCharWidth = os2[2] * 256 + os2[3];
        m_avgCharWidth = scaleEmToUnits(os2AvgCharWidth, m_fontMetrics.unitsPerEm()) * m_platformData.m_size;
    }

    RetainPtr<CFDataRef> headTable(AdoptCF, copyFontTableForTag(m_platformData, 'head'));
    if (headTable && CFDataGetLength(headTable.get()) >= 42) {
        const UInt8* head = CFDataGetBytePtr(headTable.get());
        ushort uxMin = head[36] * 256 + head[37];
        ushort uxMax = head[40] * 256 + head[41];
        SInt16 xMin = static_cast<SInt16>(uxMin);
        SInt16 xMax = static_cast<SInt16>(uxMax);
        float diff = static_cast<float>(xMax - xMin);
        m_maxCharWidth = scaleEmToUnits(diff, m_fontMetrics.unitsPerEm()) * m_platformData.m_size;
    }

    // Fallback to a cross-platform estimate, which will populate these values if they are non-positive.
    initCharWidths();
}

void SimpleFontData::platformDestroy()
{
    if (!isCustomFont() && m_derivedFontData) {
        // These come from the cache.
        if (m_derivedFontData->smallCaps)
            fontCache()->releaseFontData(m_derivedFontData->smallCaps.get());

        if (m_derivedFontData->emphasisMark)
            fontCache()->releaseFontData(m_derivedFontData->emphasisMark.get());
    }
}

PassRefPtr<SimpleFontData> SimpleFontData::platformCreateScaledFontData(const FontDescription& fontDescription, float scaleFactor) const
{
    if (isCustomFont()) {
        FontPlatformData scaledFontData(m_platformData);
        scaledFontData.m_size = scaledFontData.m_size * scaleFactor;
        return SimpleFontData::create(scaledFontData, true, false);
    }

    BEGIN_BLOCK_OBJC_EXCEPTIONS;
    float size = m_platformData.size() * scaleFactor;
    FontPlatformData scaledFontData([[NSFontManager sharedFontManager] convertFont:m_platformData.font() toSize:size], size, m_platformData.isPrinterFont(), false, false, m_platformData.orientation());

    // AppKit resets the type information (screen/printer) when you convert a font to a different size.
    // We have to fix up the font that we're handed back.
    scaledFontData.setFont(fontDescription.usePrinterFont() ? [scaledFontData.font() printerFont] : [scaledFontData.font() screenFont]);

    if (scaledFontData.font()) {
        NSFontManager *fontManager = [NSFontManager sharedFontManager];
        NSFontTraitMask fontTraits = [fontManager traitsOfFont:m_platformData.font()];

        if (m_platformData.m_syntheticBold)
            fontTraits |= NSBoldFontMask;
        if (m_platformData.m_syntheticOblique)
            fontTraits |= NSItalicFontMask;

        NSFontTraitMask scaledFontTraits = [fontManager traitsOfFont:scaledFontData.font()];
        scaledFontData.m_syntheticBold = (fontTraits & NSBoldFontMask) && !(scaledFontTraits & NSBoldFontMask);
        scaledFontData.m_syntheticOblique = (fontTraits & NSItalicFontMask) && !(scaledFontTraits & NSItalicFontMask);

        // SimpleFontData::platformDestroy() takes care of not deleting the cached font data twice.
        return fontCache()->getFontResourceData(&scaledFontData);
    }
    END_BLOCK_OBJC_EXCEPTIONS;

    return 0;
}

bool SimpleFontData::containsCharacters(const UChar* characters, int length) const
{
    NSString *string = [[NSString alloc] initWithCharactersNoCopy:const_cast<unichar*>(characters) length:length freeWhenDone:NO];
    NSCharacterSet *set = [[m_platformData.font() coveredCharacterSet] invertedSet];
    bool result = set && [string rangeOfCharacterFromSet:set].location == NSNotFound;
    [string release];
    return result;
}

void SimpleFontData::determinePitch()
{
    NSFont* f = m_platformData.font();
    // Special case Osaka-Mono.
    // According to <rdar://problem/3999467>, we should treat Osaka-Mono as fixed pitch.
    // Note that the AppKit does not report Osaka-Mono as fixed pitch.

    // Special case MS-PGothic.
    // According to <rdar://problem/4032938>, we should not treat MS-PGothic as fixed pitch.
    // Note that AppKit does report MS-PGothic as fixed pitch.

    // Special case MonotypeCorsiva
    // According to <rdar://problem/5454704>, we should not treat MonotypeCorsiva as fixed pitch.
    // Note that AppKit does report MonotypeCorsiva as fixed pitch.

    NSString *name = [f fontName];
    m_treatAsFixedPitch = ([f isFixedPitch] || [f _isFakeFixedPitch] ||
           [name caseInsensitiveCompare:@"Osaka-Mono"] == NSOrderedSame) &&
           [name caseInsensitiveCompare:@"MS-PGothic"] != NSOrderedSame &&
           [name caseInsensitiveCompare:@"MonotypeCorsiva"] != NSOrderedSame;
}

FloatRect SimpleFontData::platformBoundsForGlyph(Glyph glyph) const
{
    FloatRect boundingBox;
    boundingBox = CTFontGetBoundingRectsForGlyphs(m_platformData.ctFont(), platformData().orientation() == Vertical ? kCTFontVerticalOrientation : kCTFontHorizontalOrientation, &glyph, 0, 1);
    boundingBox.setY(-boundingBox.maxY());
    if (m_syntheticBoldOffset)
        boundingBox.setWidth(boundingBox.width() + m_syntheticBoldOffset);

    return boundingBox;
}

float SimpleFontData::platformWidthForGlyph(Glyph glyph) const
{
    CGSize advance = CGSizeZero;
    if (platformData().orientation() == Horizontal || m_isBrokenIdeographFallback) {
        NSFont *font = platformData().font();
        if (font && platformData().isColorBitmapFont())
            advance = NSSizeToCGSize([font advancementForGlyph:glyph]);
        else {
            float pointSize = platformData().m_size;
            CGAffineTransform m = CGAffineTransformMakeScale(pointSize, pointSize);
            if (!CGFontGetGlyphAdvancesForStyle(platformData().cgFont(), &m, cgFontRenderingModeForNSFont(font), &glyph, 1, &advance)) {
                LOG_ERROR("Unable to cache glyph widths for %@ %f", [font displayName], pointSize);
                advance.width = 0;
            }
        }
    } else
        CTFontGetAdvancesForGlyphs(m_platformData.ctFont(), kCTFontVerticalOrientation, &glyph, &advance, 1);

    return advance.width + m_syntheticBoldOffset;
}

struct ProviderInfo {
    const UChar* characters;
    size_t length;
    CFDictionaryRef attributes;
};

static const UniChar* provideStringAndAttributes(CFIndex stringIndex, CFIndex* count, CFDictionaryRef* attributes, void* context)
{
    ProviderInfo* info = static_cast<struct ProviderInfo*>(context);
    if (stringIndex < 0 || static_cast<size_t>(stringIndex) >= info->length)
        return 0;

    *count = info->length - stringIndex;
    *attributes = info->attributes;
    return info->characters + stringIndex;
}

bool SimpleFontData::canRenderCombiningCharacterSequence(const UChar* characters, size_t length) const
{
    ASSERT(isMainThread());

    if (!m_combiningCharacterSequenceSupport)
        m_combiningCharacterSequenceSupport = adoptPtr(new HashMap<String, bool>);

    WTF::HashMap<String, bool>::AddResult addResult = m_combiningCharacterSequenceSupport->add(String(characters, length), false);
    if (!addResult.isNewEntry)
        return addResult.iterator->value;

    RetainPtr<CGFontRef> cgFont(AdoptCF, CTFontCopyGraphicsFont(platformData().ctFont(), 0));

    ProviderInfo info = { characters, length, getCFStringAttributes(0, platformData().orientation()) };
    RetainPtr<CTLineRef> line(AdoptCF, CTLineCreateWithUniCharProvider(&provideStringAndAttributes, 0, &info));

    CFArrayRef runArray = CTLineGetGlyphRuns(line.get());
    CFIndex runCount = CFArrayGetCount(runArray);

    for (CFIndex r = 0; r < runCount; r++) {
        CTRunRef ctRun = static_cast<CTRunRef>(CFArrayGetValueAtIndex(runArray, r));
        ASSERT(CFGetTypeID(ctRun) == CTRunGetTypeID());
        CFDictionaryRef runAttributes = CTRunGetAttributes(ctRun);
        CTFontRef runFont = static_cast<CTFontRef>(CFDictionaryGetValue(runAttributes, kCTFontAttributeName));
        RetainPtr<CGFontRef> runCGFont(AdoptCF, CTFontCopyGraphicsFont(runFont, 0));
        if (!CFEqual(runCGFont.get(), cgFont.get()))
            return false;
    }

    addResult.iterator->value = true;
    return true;
}

} // namespace WebCore