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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/gfx/image/image_family.h"
#include <cmath>
#include "skia/ext/image_operations.h"
#include "ui/gfx/geometry/size.h"
#include "ui/gfx/image/image.h"
#include "ui/gfx/image/image_skia.h"
namespace gfx {
ImageFamily::const_iterator::const_iterator() {}
ImageFamily::const_iterator::const_iterator(const const_iterator& other)
: map_iterator_(other.map_iterator_) {}
ImageFamily::const_iterator::const_iterator(
const std::map<MapKey, gfx::Image>::const_iterator& other)
: map_iterator_(other) {}
ImageFamily::const_iterator::~const_iterator() {}
ImageFamily::ImageFamily() {}
ImageFamily::~ImageFamily() {}
void ImageFamily::Add(const gfx::Image& image) {
gfx::Size size = image.Size();
if (size.IsEmpty()) {
map_[MapKey(1.0f, 0)] = image;
} else {
float aspect = static_cast<float>(size.width()) / size.height();
DCHECK_GT(aspect, 0.0f);
map_[MapKey(aspect, size.width())] = image;
}
}
void ImageFamily::Add(const gfx::ImageSkia& image_skia) {
Add(gfx::Image(image_skia));
}
const gfx::Image* ImageFamily::GetBest(int width, int height) const {
if (map_.empty())
return NULL;
// If either |width| or |height| is 0, both are.
float desired_aspect;
if (height == 0 || width == 0) {
desired_aspect = 1.0f;
height = 0;
width = 0;
} else {
desired_aspect = static_cast<float>(width) / height;
}
DCHECK_GT(desired_aspect, 0.0f);
float closest_aspect = GetClosestAspect(desired_aspect);
// If thinner than desired, search for images with width such that the
// corresponding height is greater than or equal to the desired |height|.
int desired_width = closest_aspect <= desired_aspect ?
width : static_cast<int>(ceilf(height * closest_aspect));
// Get the best-sized image with the aspect ratio.
return GetWithExactAspect(closest_aspect, desired_width);
}
float ImageFamily::GetClosestAspect(float desired_aspect) const {
// Find the two aspect ratios on either side of |desired_aspect|.
std::map<MapKey, gfx::Image>::const_iterator greater_or_equal =
map_.lower_bound(MapKey(desired_aspect, 0));
// Early exit optimization if there is an exact match.
if (greater_or_equal != map_.end() &&
greater_or_equal->first.aspect() == desired_aspect) {
return desired_aspect;
}
// No exact match; |greater_or_equal| will point to the first image with
// aspect ratio >= |desired_aspect|, and |less_than| will point to the last
// image with aspect ratio < |desired_aspect|.
if (greater_or_equal != map_.begin()) {
std::map<MapKey, gfx::Image>::const_iterator less_than =
greater_or_equal;
--less_than;
float thinner_aspect = less_than->first.aspect();
DCHECK_GT(thinner_aspect, 0.0f);
DCHECK_LT(thinner_aspect, desired_aspect);
if (greater_or_equal != map_.end()) {
float wider_aspect = greater_or_equal->first.aspect();
DCHECK_GT(wider_aspect, desired_aspect);
if ((wider_aspect / desired_aspect) < (desired_aspect / thinner_aspect))
return wider_aspect;
}
return thinner_aspect;
} else {
// No aspect ratio is less than or equal to |desired_aspect|.
DCHECK(greater_or_equal != map_.end());
float wider_aspect = greater_or_equal->first.aspect();
DCHECK_GT(wider_aspect, desired_aspect);
return wider_aspect;
}
}
const gfx::Image* ImageFamily::GetBest(const gfx::Size& size) const {
return GetBest(size.width(), size.height());
}
gfx::Image ImageFamily::CreateExact(int width, int height) const {
// Resize crashes if width or height is 0, so just return an empty image.
if (width == 0 || height == 0)
return gfx::Image();
const gfx::Image* image = GetBest(width, height);
if (!image)
return gfx::Image();
if (image->Width() == width && image->Height() == height) {
// Make a copy at gfx::ImageSkia level, so that resulting image's ref count
// is not racy to |image|. Since this function can run on a different thread
// than the thread |image| created on, we should not touch the
// non-thread-safe ref count in gfx::Image here.
std::unique_ptr<gfx::ImageSkia> image_skia(image->CopyImageSkia());
return gfx::Image(*image_skia);
}
SkBitmap bitmap = image->AsBitmap();
SkBitmap resized_bitmap = skia::ImageOperations::Resize(
bitmap, skia::ImageOperations::RESIZE_LANCZOS3, width, height);
return gfx::Image::CreateFrom1xBitmap(resized_bitmap);
}
gfx::Image ImageFamily::CreateExact(const gfx::Size& size) const {
return CreateExact(size.width(), size.height());
}
const gfx::Image* ImageFamily::GetWithExactAspect(float aspect,
int width) const {
// Find the two images of given aspect ratio on either side of |width|.
std::map<MapKey, gfx::Image>::const_iterator greater_or_equal =
map_.lower_bound(MapKey(aspect, width));
if (greater_or_equal != map_.end() &&
greater_or_equal->first.aspect() == aspect) {
// We have found the smallest image of the same size or greater.
return &greater_or_equal->second;
}
DCHECK(greater_or_equal != map_.begin());
std::map<MapKey, gfx::Image>::const_iterator less_than = greater_or_equal;
--less_than;
// This must be true because there must be at least one image with |aspect|.
DCHECK_EQ(less_than->first.aspect(), aspect);
// We have found the largest image smaller than desired.
return &less_than->second;
}
} // namespace gfx
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