| /* |
| * Copyright (C) 2015 Frederic Wang (fred.wang@free.fr). All rights reserved. |
| * |
| * 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 THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT |
| * OWNER OR 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. |
| */ |
| |
| #include "config.h" |
| #include "OpenTypeCG.h" |
| |
| #include "OpenTypeTypes.h" |
| |
| namespace WebCore { |
| namespace OpenType { |
| |
| #if PLATFORM(WIN) |
| static const unsigned long kCTFontTableOS2 = 'OS/2'; |
| #endif |
| |
| bool fontHasMathTable(CTFontRef ctFont) |
| { |
| RetainPtr<CFArrayRef> tableTags = adoptCF(CTFontCopyAvailableTables(ctFont, kCTFontTableOptionNoOptions)); |
| if (!tableTags) |
| return false; |
| CFIndex numTables = CFArrayGetCount(tableTags.get()); |
| for (CFIndex index = 0; index < numTables; ++index) { |
| CTFontTableTag tag = (CTFontTableTag)(uintptr_t)CFArrayGetValueAtIndex(tableTags.get(), index); |
| if (tag == 'MATH') |
| return true; |
| } |
| return false; |
| } |
| |
| static inline short readShortFromTable(const UInt8* os2Data, CFIndex offset) |
| { |
| return *(reinterpret_cast<const OpenType::Int16*>(os2Data + offset)); |
| } |
| |
| bool tryGetTypoMetrics(CTFontRef font, short& ascent, short& descent, short& lineGap) |
| { |
| bool result = false; |
| if (auto os2Table = adoptCF(CTFontCopyTable(font, kCTFontTableOS2, kCTFontTableOptionNoOptions))) { |
| // For the structure of the OS/2 table, see |
| // https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6OS2.html |
| const CFIndex fsSelectionOffset = 16 * 2 + 10 + 4 * 4 + 4 * 1; |
| const CFIndex sTypoAscenderOffset = fsSelectionOffset + 3 * 2; |
| const CFIndex sTypoDescenderOffset = sTypoAscenderOffset + 2; |
| const CFIndex sTypoLineGapOffset = sTypoDescenderOffset + 2; |
| if (CFDataGetLength(os2Table.get()) >= sTypoLineGapOffset + 2) { |
| const UInt8* os2Data = CFDataGetBytePtr(os2Table.get()); |
| // We test the use typo bit on the least significant byte of fsSelection. |
| const UInt8 useTypoMetricsMask = 1 << 7; |
| if (*(os2Data + fsSelectionOffset + 1) & useTypoMetricsMask) { |
| ascent = readShortFromTable(os2Data, sTypoAscenderOffset); |
| descent = readShortFromTable(os2Data, sTypoDescenderOffset); |
| lineGap = readShortFromTable(os2Data, sTypoLineGapOffset); |
| result = true; |
| } |
| } |
| } |
| return result; |
| } |
| |
| } // namespace OpenType |
| } // namespace WebCore |