| /* |
| * Copyright (C) 2000 Lars Knoll (knoll@kde.org) |
| * (C) 2000 Antti Koivisto (koivisto@kde.org) |
| * (C) 2000 Dirk Mueller (mueller@kde.org) |
| * Copyright (C) 2003, 2006, 2007, 2010, 2011 Apple Inc. All rights reserved. |
| * Copyright (C) 2008 Holger Hans Peter Freyther |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Library General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Library General Public License for more details. |
| * |
| * You should have received a copy of the GNU Library General Public License |
| * along with this library; see the file COPYING.LIB. If not, write to |
| * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
| * Boston, MA 02110-1301, USA. |
| * |
| */ |
| |
| #ifndef GlyphOverflow_h |
| #define GlyphOverflow_h |
| |
| #include "platform/geometry/FloatRect.h" |
| #include "wtf/Allocator.h" |
| #include <algorithm> |
| |
| namespace blink { |
| |
| struct GlyphOverflow { |
| GlyphOverflow() : left(0), right(0), top(0), bottom(0) {} |
| |
| bool isApproximatelyZero() const { |
| // Overflow can be expensive so we try to avoid it. Small amounts of |
| // overflow is imperceptible and is typically masked by pixel snapping. |
| static const float kApproximatelyNoOverflow = 0.0625f; |
| return std::fabs(left) < kApproximatelyNoOverflow && |
| std::fabs(right) < kApproximatelyNoOverflow && |
| std::fabs(top) < kApproximatelyNoOverflow && |
| std::fabs(bottom) < kApproximatelyNoOverflow; |
| } |
| |
| void setFromBounds(const FloatRect& bounds, |
| float ascent, |
| float descent, |
| float textWidth) { |
| top = std::max(0.0f, -bounds.y() - ascent); |
| bottom = std::max(0.0f, bounds.maxY() - descent); |
| left = std::max(0.0f, -bounds.x()); |
| right = std::max(0.0f, bounds.maxX() - textWidth); |
| } |
| |
| // Top and bottom are the amounts of glyph overflows exceeding the font |
| // metrics' ascent and descent, respectively. Left and right are the amounts |
| // of glyph overflows exceeding the left and right edge of normal layout |
| // boundary, respectively. |
| float left; |
| float right; |
| float top; |
| float bottom; |
| }; |
| |
| } // namespace blink |
| |
| #endif // GlyphOverflow_h |