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/*
* 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
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