(Views only) Add a gradient background to the tabstrip of the view tabbed pane implementation.

ui/views/painter.cc

 // Copyright (c) 2012 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/views/painter.h"
 
 #include "base/logging.h"
 #include "third_party/skia/include/effects/SkGradientShader.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/image/image.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/insets.h"
 #include "ui/gfx/point.h"
 #include "ui/gfx/rect.h"
 
 namespace views {
 
 namespace {
 
 class GradientPainter : public Painter {
  public:
-  GradientPainter(bool horizontal, SkColor top, SkColor bottom)
-      : horizontal_(horizontal) {
+  GradientPainter(bool horizontal, SkColor top, SkColor bottom, double start,

[msw, 2012/08/08 17:12:20]

nit: one param per line

[markusheintz_, 2012/08/08 21:53:55]

Done.

+                  double end)
+      : horizontal_(horizontal),
+        start_(start),
+        end_(end) {
     colors_[0] = top;
     colors_[1] = bottom;
   }
 
   virtual ~GradientPainter() {
   }
 
   // Overridden from Painter:
   virtual void Paint(gfx::Canvas* canvas, const gfx::Size& size) OVERRIDE {
     SkPaint paint;
     SkPoint p[2];
-    p[0].iset(0, 0);
-    if (horizontal_)
-      p[1].iset(size.width(), 0);
-    else
-      p[1].iset(0, size.height());
+    if (horizontal_) {
+      p[0].iset(size.width() * start_, 0);
+      p[1].iset(size.width() * end_, 0);
+    } else {
+      p[0].iset(0, size.height() * start_);
+      p[1].iset(0, size.height() * end_);
+    }
 
     SkShader* s = SkGradientShader::CreateLinear(p, colors_, NULL, 2,
         SkShader::kClamp_TileMode, NULL);
     paint.setStyle(SkPaint::kFill_Style);
     paint.setShader(s);
     // Need to unref shader, otherwise never deleted.
     s->unref();
 
     canvas->sk_canvas()->drawRectCoords(SkIntToScalar(0), SkIntToScalar(0),
                                         SkIntToScalar(size.width()),
                                         SkIntToScalar(size.height()), paint);
   }
 
  private:
+  // If |horizontal_| is true then the gradiant is painted horizontally.
   bool horizontal_;
+  // The start and the end color of the gradient.
   SkColor colors_[2];
+  // The start of the gradient specified as percentage of the total size of the

[msw, 2012/08/08 17:12:20]

nit: s/percentage/ratio/, ditto below

[markusheintz_, 2012/08/08 21:53:55]

obsolete

+  // background.
+  double start_;

[msw, 2012/08/08 17:12:20]

Consider using SkScalar/floats here, instead of doubles (for use in SkPoints).

[markusheintz_, 2012/08/08 21:53:55]

Done.

+  // The end of the gradient specified as percentage of the total size of the
+  // background.
+  double end_;
 
   DISALLOW_COPY_AND_ASSIGN(GradientPainter);
 };
 
 
 class ImagePainter : public Painter {
  public:
   ImagePainter(const gfx::ImageSkia& image,
                const gfx::Insets& insets,
                bool paint_center)
@@ skipping 89 matching lines @@
                              const gfx::Rect& rect) {
   DCHECK(canvas && painter);
   canvas->Save();
   canvas->Translate(rect.origin());
   painter->Paint(canvas, rect.size());
   canvas->Restore();
 }
 
 // static
 Painter* Painter::CreateHorizontalGradient(SkColor c1, SkColor c2) {
-  return new GradientPainter(true, c1, c2);
+  return new GradientPainter(true, c1, c2, 0.0f, 1.0f);
 }
 
 // static
 Painter* Painter::CreateVerticalGradient(SkColor c1, SkColor c2) {
-  return new GradientPainter(false, c1, c2);
+  return new GradientPainter(false, c1, c2, 0.0f, 1.0f);
 }
 
 // static
+Painter* Painter::CreateVerticalGradientRange(
+    SkColor c1, SkColor c2, float start, float end) {

[msw, 2012/08/08 17:12:20]

nit: one param per line

[markusheintz_, 2012/08/08 21:53:55]

Done.

+  return new GradientPainter(false, c1, c2, start, end);
+}
+
+// static
 Painter* Painter::CreateImagePainter(const gfx::ImageSkia& image,
                                      const gfx::Insets& insets,
                                      bool paint_center) {
   return new ImagePainter(image, insets, paint_center);
 }
 
 HorizontalPainter::HorizontalPainter(const int image_resource_names[]) {
   ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
   for (int i = 0; i < 3; ++i)
     images_[i] = rb.GetImageNamed(image_resource_names[i]).ToImageSkia();
   height_ = images_[LEFT]->height();
   DCHECK(images_[LEFT]->height() == images_[RIGHT]->height() &&
          images_[LEFT]->height() == images_[CENTER]->height());
 }
 
 void HorizontalPainter::Paint(gfx::Canvas* canvas, const gfx::Size& size) {
   if (size.width() < (images_[LEFT]->width() + images_[CENTER]->width() +
       images_[RIGHT]->width())) {
     // No room to paint.
     return;
   }
   canvas->DrawImageInt(*images_[LEFT], 0, 0);
   canvas->DrawImageInt(*images_[RIGHT],
                        size.width() - images_[RIGHT]->width(), 0);
   canvas->TileImageInt(*images_[CENTER], images_[LEFT]->width(), 0,
       size.width() - images_[LEFT]->width() - images_[RIGHT]->width(), height_);
 }
 
 }  // namespace views