[gtk] spoof proof infobars, take 2

This looks like a big review, but a lot of it is just shuffling code around:
- rip out dropshadow code
- move arrow state and drawing to a model class, to allow sharing between BrowserWindow and Infobar
- get rid of InfoBar's border_bin_ and slightly simplify baseclasses by no longer requiring them to call show() on the toplevel widget

Added stuff:
- transition between arrow colors (previous_color_ vs. target_color_ business)
- arrows protruding on neighboring infobars

BUG=48996
TEST=manual, with animations slowed down 100x

Review URL: http://codereview.chromium.org/3919004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@63956 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 124 insertions, 0 deletions

diff --git a/chrome/browser/gtk/infobar_arrow_model.cc b/chrome/browser/gtk/infobar_arrow_model.cc
new file mode 100644
index 0000000..e66bb02
--- /dev/null
+++ b/chrome/browser/gtk/infobar_arrow_model.cc
@@ -0,0 +1,124 @@
+// Copyright (c) 2010 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 "chrome/browser/gtk/infobar_arrow_model.h"
+
+#include "chrome/browser/gtk/infobar_gtk.h"
+#include "gfx/canvas_skia_paint.h"
+#include "gfx/color_utils.h"
+#include "gfx/point.h"
+#include "gfx/skia_utils_gtk.h"
+#include "third_party/skia/include/effects/SkGradientShader.h"
+
+InfoBarArrowModel::InfoBarArrowModel(Observer* observer)
+    : observer_(observer),
+      animation_(this) {
+  animation_.SetTweenType(Tween::LINEAR);
+  animation_.Reset(1.0);
+  target_colors_.top = target_colors_.bottom = SkColorSetARGB(0, 0, 0, 0);
+  previous_colors_ = target_colors_;
+}
+
+InfoBarArrowModel::~InfoBarArrowModel() {
+}
+
+InfoBarArrowModel::InfoBarColors InfoBarArrowModel::CurrentInfoBarColors() {
+  double alpha = animation_.GetCurrentValue();
+  InfoBarColors colors = {
+      color_utils::AlphaBlend(target_colors_.top,
+                              previous_colors_.top,
+                              alpha * 0xff),
+      color_utils::AlphaBlend(target_colors_.bottom,
+                              previous_colors_.bottom,
+                              alpha * 0xff)};
+  return colors;
+}
+
+bool InfoBarArrowModel::NeedToDrawInfoBarArrow() {
+  return SkColorGetA(CurrentInfoBarColors().top) != 0;
+}
+
+void InfoBarArrowModel::ShowArrowFor(InfoBar* bar, bool animate) {
+  scoped_ptr<std::pair<SkColor, SkColor> > colors;
+
+  previous_colors_ = CurrentInfoBarColors();
+
+  if (bar) {
+    double r, g, b;
+    bar->GetTopColor(bar->delegate()->GetInfoBarType(), &r, &g, &b);
+    target_colors_.top = SkColorSetRGB(r * 0xff, g * 0xff, b * 0xff);
+    bar->GetBottomColor(bar->delegate()->GetInfoBarType(), &r, &g, &b);
+    target_colors_.bottom = SkColorSetRGB(r * 0xff, g * 0xff, b * 0xff);
+  } else {
+    target_colors_.bottom = target_colors_.top = SkColorSetARGB(0, 0, 0, 0);
+  }
+
+  if (animate) {
+    // Fade from the current color to the target color.
+    animation_.Reset();
+    animation_.Show();
+  } else {
+    // Skip straight to showing the target color.
+    animation_.Reset(1.0);
+  }
+
+  observer_->PaintStateChanged();
+}
+
+void InfoBarArrowModel::Paint(GtkWidget* widget,
+                              GdkEventExpose* expose,
+                              const gfx::Point& origin,
+                              const GdkColor& border_color) {
+  if (!NeedToDrawInfoBarArrow())
+    return;
+
+  // The size of the arrow (its height; also half its width).
+  const int kArrowSize = 10;
+
+  SkPath path;
+  path.moveTo(SkPoint::Make(origin.x() - kArrowSize, origin.y()));
+  path.rLineTo(kArrowSize, -kArrowSize);
+  path.rLineTo(kArrowSize, kArrowSize);
+  path.close();
+
+  SkPaint paint;
+  paint.setStrokeWidth(1);
+  paint.setStyle(SkPaint::kFill_Style);
+
+  SkPoint grad_points[2];
+  grad_points[0].set(SkIntToScalar(0), SkIntToScalar(origin.y()));
+  grad_points[1].set(SkIntToScalar(0),
+                     SkIntToScalar(origin.y() + InfoBar::kInfoBarHeight));
+
+  InfoBarColors colors = CurrentInfoBarColors();
+  SkColor grad_colors[2];
+  grad_colors[0] = colors.top;
+  grad_colors[1] = colors.bottom;
+
+  SkShader* gradient_shader = SkGradientShader::CreateLinear(
+      grad_points, grad_colors, NULL, 2, SkShader::kMirror_TileMode);
+  paint.setShader(gradient_shader);
+  gradient_shader->unref();
+
+  gfx::CanvasSkiaPaint canvas(expose, false);
+  canvas.drawPath(path, paint);
+
+  paint.setShader(NULL);
+  paint.setColor(SkColorSetA(gfx::GdkColorToSkColor(border_color),
+                             SkColorGetA(colors.top)));
+  paint.setStyle(SkPaint::kStroke_Style);
+  canvas.drawPath(path, paint);
+}
+
+void InfoBarArrowModel::AnimationEnded(const Animation* animation) {
+  observer_->PaintStateChanged();
+}
+
+void InfoBarArrowModel::AnimationProgressed(const Animation* animation) {
+  observer_->PaintStateChanged();
+}
+
+void InfoBarArrowModel::AnimationCanceled(const Animation* animation) {
+  observer_->PaintStateChanged();
+}