[UI] Support icons and secondary labels in combobox

The underlying dropdown menu model already supports showing icons and
secondary labels.

This CL add such support to the combobox model. When an item is selected
the main label is shown inside in the combobox together with the icon.
Secondary labels are displayed only inside the dropdown menu.

Bug: 1044038
Change-Id: Ibe3cc37464bfd8e416aeadec62827b8ca103d13f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2207386
Commit-Queue: Mohamed Amir Yosef <mamir@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#770807}

ui/base/models/combobox_model.cc

@@ -4,8 +4,18 @@
 
 #include "ui/base/models/combobox_model.h"
 
+#include "ui/base/models/image_model.h"
+
 namespace ui {
 
+base::string16 ComboboxModel::GetDropDownSecondaryTextAt(int index) const {
+  return base::string16();
+}
+
+ImageModel ComboboxModel::GetIconAt(int index) const {
+  return ui::ImageModel();
+}
+
 bool ComboboxModel::IsItemSeparatorAt(int index) {
   return false;
 }

ui/base/models/combobox_model.h

@@ -11,6 +11,7 @@
 namespace ui {
 
 class ComboboxModelObserver;
+class ImageModel;
 
 // A data model for a combo box.
 class UI_BASE_EXPORT ComboboxModel {
@@ -23,6 +24,14 @@ class UI_BASE_EXPORT ComboboxModel {
   // Returns the string at the specified index.
   virtual base::string16 GetItemAt(int index) = 0;
 
+  // Returns the secondary string at the specified index. Secondary strings are
+  // displayed in a second line inside every menu item.
+  virtual base::string16 GetDropDownSecondaryTextAt(int index) const;
+
+  // Gets the icon for the item at the specified index. ImageModel is empty if
+  // there is no icon.
+  virtual ImageModel GetIconAt(int index) const;
+
   // Should return true if the item at |index| is a non-selectable separator
   // item.
   virtual bool IsItemSeparatorAt(int index);

ui/views/controls/combobox/combobox.cc

@@ -132,7 +132,13 @@ class Combobox::ComboboxMenuModel : public ui::MenuModel {
   }
 
   // Overridden from MenuModel:
-  bool HasIcons() const override { return false; }
+  bool HasIcons() const override {
+    for (int i = 0; i < GetItemCount(); ++i) {
+      if (!GetIconAt(i).IsEmpty())
+        return true;
+    }
+    return false;
+  }
 
   int GetItemCount() const override { return model_->GetItemCount(); }
 
@@ -160,6 +166,12 @@ class Combobox::ComboboxMenuModel : public ui::MenuModel {
     return text;
   }
 
+  base::string16 GetSecondaryLabelAt(int index) const override {
+    base::string16 text = model_->GetDropDownSecondaryTextAt(index);
+    base::i18n::AdjustStringForLocaleDirection(&text);
+    return text;
+  }
+
   bool IsItemDynamicAt(int index) const override { return true; }
 
   const gfx::FontList* GetLabelFontListAt(int index) const override {
@@ -178,7 +190,7 @@ class Combobox::ComboboxMenuModel : public ui::MenuModel {
   int GetGroupIdAt(int index) const override { return -1; }
 
   ui::ImageModel GetIconAt(int index) const override {
-    return ui::ImageModel();
+    return model_->GetIconAt(index);
   }
 
   ui::ButtonMenuItemModel* GetButtonMenuItemAt(int index) const override {
@@ -443,7 +455,7 @@ bool Combobox::OnKeyPressed(const ui::KeyEvent& e) {
 
 void Combobox::OnPaint(gfx::Canvas* canvas) {
   OnPaintBackground(canvas);
-  PaintText(canvas);
+  PaintIconAndText(canvas);
   OnPaintBorder(canvas);
 }
 
@@ -543,7 +555,7 @@ void Combobox::AdjustBoundsForRTLUI(gfx::Rect* rect) const {
   rect->set_x(GetMirroredXForRect(*rect));
 }
 
-void Combobox::PaintText(gfx::Canvas* canvas) {
+void Combobox::PaintIconAndText(gfx::Canvas* canvas) {
   gfx::Insets insets = GetInsets();
   insets += gfx::Insets(0, LayoutProvider::Get()->GetDistanceMetric(
                                DISTANCE_TEXTFIELD_HORIZONTAL_TEXT_PADDING));
@@ -553,7 +565,19 @@ void Combobox::PaintText(gfx::Canvas* canvas) {
 
   int x = insets.left();
   int y = insets.top();
-  int text_height = height() - insets.height();
+  int contents_height = height() - insets.height();
+
+  // Draw the icon.
+  ui::ImageModel icon = model()->GetIconAt(selected_index_);
+  if (!icon.IsEmpty()) {
+    gfx::Image icon_image = icon.GetImage();
+    int icon_y = y + (contents_height - icon_image.Height()) / 2;
+    canvas->DrawImageInt(icon_image.AsImageSkia(), x, icon_y);
+    x += icon_image.Width() + LayoutProvider::Get()->GetDistanceMetric(
+                                  DISTANCE_RELATED_LABEL_HORIZONTAL);
+  }
+
+  // Draw the text.
   SkColor text_color = GetTextColorForEnableState(*this, GetEnabled());
   DCHECK_GE(selected_index_, 0);
   DCHECK_LT(selected_index_, model()->GetItemCount());
@@ -565,10 +589,10 @@ void Combobox::PaintText(gfx::Canvas* canvas) {
 
   const gfx::FontList& font_list = GetFontList();
   int text_width = gfx::GetStringWidth(text, font_list);
-  if ((text_width + insets.width()) > disclosure_arrow_offset)
-    text_width = disclosure_arrow_offset - insets.width();
+  text_width =
+      std::min(text_width, disclosure_arrow_offset - insets.right() - x);
 
-  gfx::Rect text_bounds(x, y, text_width, text_height);
+  gfx::Rect text_bounds(x, y, text_width, contents_height);
   AdjustBoundsForRTLUI(&text_bounds);
   canvas->DrawStringRect(text, font_list, text_color, text_bounds);
 
@@ -633,18 +657,25 @@ void Combobox::OnPerformAction() {
 
 gfx::Size Combobox::GetContentSize() const {
   const gfx::FontList& font_list = GetFontList();
-
+  int height = font_list.GetHeight();
   int width = 0;
   for (int i = 0; i < model()->GetItemCount(); ++i) {
     if (model_->IsItemSeparatorAt(i))
       continue;
 
     if (size_to_largest_label_ || i == selected_index_) {
-      width = std::max(
-          width, gfx::GetStringWidth(menu_model_->GetLabelAt(i), font_list));
+      int item_width =
+          gfx::GetStringWidth(menu_model_->GetLabelAt(i), font_list);
+      if (!menu_model_->GetIconAt(i).IsEmpty()) {
+        gfx::Image icon = menu_model_->GetIconAt(i).GetImage();
+        item_width += icon.Width() + LayoutProvider::Get()->GetDistanceMetric(
+                                         DISTANCE_RELATED_LABEL_HORIZONTAL);
+        height = std::max(height, icon.Height());
+      }
+      width = std::max(width, item_width);
     }
   }
-  return gfx::Size(width, font_list.GetHeight());
+  return gfx::Size(width, height);
 }
 
 PrefixSelector* Combobox::GetPrefixSelector() {

ui/views/controls/combobox/combobox.h

@@ -126,7 +126,7 @@ class VIEWS_EXPORT Combobox : public View,
   void AdjustBoundsForRTLUI(gfx::Rect* rect) const;
 
   // Draws the selected value of the drop down list
-  void PaintText(gfx::Canvas* canvas);
+  void PaintIconAndText(gfx::Canvas* canvas);
 
   // Show the drop down list
   void ShowDropDownMenu(ui::MenuSourceType source_type);