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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "ui/views/controls/image_view.h"
      6 
      7 #include "base/logging.h"
      8 #include "base/strings/utf_string_conversions.h"
      9 #include "third_party/skia/include/core/SkPaint.h"
     10 #include "ui/accessibility/ax_view_state.h"
     11 #include "ui/gfx/canvas.h"
     12 #include "ui/gfx/insets.h"
     13 #include "ui/views/painter.h"
     14 
     15 namespace views {
     16 
     17 namespace {
     18 
     19 // Returns the pixels for the bitmap in |image| at scale |image_scale|.
     20 void* GetBitmapPixels(const gfx::ImageSkia& img, float image_scale) {
     21   DCHECK_NE(0.0f, image_scale);
     22   const SkBitmap& bitmap = img.GetRepresentation(image_scale).sk_bitmap();
     23   SkAutoLockPixels pixel_lock(bitmap);
     24   return bitmap.getPixels();
     25 }
     26 
     27 }  // namespace
     28 
     29 ImageView::ImageView()
     30     : image_size_set_(false),
     31       horiz_alignment_(CENTER),
     32       vert_alignment_(CENTER),
     33       interactive_(true),
     34       last_paint_scale_(0.f),
     35       last_painted_bitmap_pixels_(NULL),
     36       focus_painter_(Painter::CreateDashedFocusPainter()) {
     37 }
     38 
     39 ImageView::~ImageView() {
     40 }
     41 
     42 void ImageView::SetImage(const gfx::ImageSkia& img) {
     43   if (IsImageEqual(img))
     44     return;
     45 
     46   last_painted_bitmap_pixels_ = NULL;
     47   gfx::Size pref_size(GetPreferredSize());
     48   image_ = img;
     49   if (pref_size != GetPreferredSize())
     50     PreferredSizeChanged();
     51   SchedulePaint();
     52 }
     53 
     54 void ImageView::SetImage(const gfx::ImageSkia* image_skia) {
     55   if (image_skia) {
     56     SetImage(*image_skia);
     57   } else {
     58     gfx::ImageSkia t;
     59     SetImage(t);
     60   }
     61 }
     62 
     63 const gfx::ImageSkia& ImageView::GetImage() {
     64   return image_;
     65 }
     66 
     67 void ImageView::SetImageSize(const gfx::Size& image_size) {
     68   image_size_set_ = true;
     69   image_size_ = image_size;
     70   PreferredSizeChanged();
     71 }
     72 
     73 bool ImageView::GetImageSize(gfx::Size* image_size) const {
     74   DCHECK(image_size);
     75   if (image_size_set_)
     76     *image_size = image_size_;
     77   return image_size_set_;
     78 }
     79 
     80 gfx::Rect ImageView::GetImageBounds() const {
     81   gfx::Size image_size(image_size_set_ ?
     82     image_size_ : gfx::Size(image_.width(), image_.height()));
     83   return gfx::Rect(ComputeImageOrigin(image_size), image_size);
     84 }
     85 
     86 void ImageView::ResetImageSize() {
     87   image_size_set_ = false;
     88 }
     89 
     90 void ImageView::SetFocusPainter(scoped_ptr<Painter> focus_painter) {
     91   focus_painter_ = focus_painter.Pass();
     92 }
     93 
     94 gfx::Size ImageView::GetPreferredSize() const {
     95   gfx::Insets insets = GetInsets();
     96   if (image_size_set_) {
     97     gfx::Size image_size;
     98     GetImageSize(&image_size);
     99     image_size.Enlarge(insets.width(), insets.height());
    100     return image_size;
    101   }
    102   return gfx::Size(image_.width() + insets.width(),
    103                    image_.height() + insets.height());
    104 }
    105 
    106 bool ImageView::IsImageEqual(const gfx::ImageSkia& img) const {
    107   // Even though we copy ImageSkia in SetImage() the backing store
    108   // (ImageSkiaStorage) is not copied and may have changed since the last call
    109   // to SetImage(). The expectation is that SetImage() with different pixels is
    110   // treated as though the image changed. For this reason we compare not only
    111   // the backing store but also the pixels of the last image we painted.
    112   return image_.BackedBySameObjectAs(img) &&
    113       last_paint_scale_ != 0.0f &&
    114       last_painted_bitmap_pixels_ == GetBitmapPixels(img, last_paint_scale_);
    115 }
    116 
    117 gfx::Point ImageView::ComputeImageOrigin(const gfx::Size& image_size) const {
    118   gfx::Insets insets = GetInsets();
    119 
    120   int x;
    121   // In order to properly handle alignment of images in RTL locales, we need
    122   // to flip the meaning of trailing and leading. For example, if the
    123   // horizontal alignment is set to trailing, then we'll use left alignment for
    124   // the image instead of right alignment if the UI layout is RTL.
    125   Alignment actual_horiz_alignment = horiz_alignment_;
    126   if (base::i18n::IsRTL() && (horiz_alignment_ != CENTER))
    127     actual_horiz_alignment = (horiz_alignment_ == LEADING) ? TRAILING : LEADING;
    128   switch (actual_horiz_alignment) {
    129     case LEADING:  x = insets.left();                                 break;
    130     case TRAILING: x = width() - insets.right() - image_size.width(); break;
    131     case CENTER:   x = (width() - image_size.width()) / 2;            break;
    132     default:       NOTREACHED(); x = 0;                               break;
    133   }
    134 
    135   int y;
    136   switch (vert_alignment_) {
    137     case LEADING:  y = insets.top();                                     break;
    138     case TRAILING: y = height() - insets.bottom() - image_size.height(); break;
    139     case CENTER:   y = (height() - image_size.height()) / 2;             break;
    140     default:       NOTREACHED(); y = 0;                                  break;
    141   }
    142 
    143   return gfx::Point(x, y);
    144 }
    145 
    146 void ImageView::OnFocus() {
    147   View::OnFocus();
    148   if (focus_painter_.get())
    149     SchedulePaint();
    150 }
    151 
    152 void ImageView::OnBlur() {
    153   View::OnBlur();
    154   if (focus_painter_.get())
    155     SchedulePaint();
    156 }
    157 
    158 void ImageView::OnPaint(gfx::Canvas* canvas) {
    159   View::OnPaint(canvas);
    160   OnPaintImage(canvas);
    161   Painter::PaintFocusPainter(this, canvas, focus_painter_.get());
    162 }
    163 
    164 void ImageView::GetAccessibleState(ui::AXViewState* state) {
    165   state->role = ui::AX_ROLE_IMAGE;
    166   state->name = tooltip_text_;
    167 }
    168 
    169 void ImageView::SetHorizontalAlignment(Alignment ha) {
    170   if (ha != horiz_alignment_) {
    171     horiz_alignment_ = ha;
    172     SchedulePaint();
    173   }
    174 }
    175 
    176 ImageView::Alignment ImageView::GetHorizontalAlignment() const {
    177   return horiz_alignment_;
    178 }
    179 
    180 void ImageView::SetVerticalAlignment(Alignment va) {
    181   if (va != vert_alignment_) {
    182     vert_alignment_ = va;
    183     SchedulePaint();
    184   }
    185 }
    186 
    187 ImageView::Alignment ImageView::GetVerticalAlignment() const {
    188   return vert_alignment_;
    189 }
    190 
    191 void ImageView::SetTooltipText(const base::string16& tooltip) {
    192   tooltip_text_ = tooltip;
    193 }
    194 
    195 base::string16 ImageView::GetTooltipText() const {
    196   return tooltip_text_;
    197 }
    198 
    199 bool ImageView::GetTooltipText(const gfx::Point& p,
    200                                base::string16* tooltip) const {
    201   if (tooltip_text_.empty())
    202     return false;
    203 
    204   *tooltip = GetTooltipText();
    205   return true;
    206 }
    207 
    208 bool ImageView::CanProcessEventsWithinSubtree() const {
    209   return interactive_;
    210 }
    211 
    212 void ImageView::OnPaintImage(gfx::Canvas* canvas) {
    213   last_paint_scale_ = canvas->image_scale();
    214   last_painted_bitmap_pixels_ = NULL;
    215 
    216   if (image_.isNull())
    217     return;
    218 
    219   gfx::Rect image_bounds(GetImageBounds());
    220   if (image_bounds.IsEmpty())
    221     return;
    222 
    223   if (image_bounds.size() != gfx::Size(image_.width(), image_.height())) {
    224     // Resize case
    225     SkPaint paint;
    226     paint.setFilterLevel(SkPaint::kLow_FilterLevel);
    227     canvas->DrawImageInt(image_, 0, 0, image_.width(), image_.height(),
    228         image_bounds.x(), image_bounds.y(), image_bounds.width(),
    229         image_bounds.height(), true, paint);
    230   } else {
    231     canvas->DrawImageInt(image_, image_bounds.x(), image_bounds.y());
    232   }
    233   last_painted_bitmap_pixels_ = GetBitmapPixels(image_, last_paint_scale_);
    234 }
    235 
    236 }  // namespace views
    237