views: Support longer tooltips.

ui/views/corewm/tooltip_aura.cc

Index: ui/views/corewm/tooltip_aura.cc
diff --git a/ui/views/corewm/tooltip_aura.cc b/ui/views/corewm/tooltip_aura.cc
index f9f41b9372255a915840a190c52eef49623bc6e7..3ae99df1ba89762010dd5854b2e109342921f0b5 100644
--- a/ui/views/corewm/tooltip_aura.cc
+++ b/ui/views/corewm/tooltip_aura.cc
@@ -5,6 +5,7 @@
 #include "ui/views/corewm/tooltip_aura.h"
 
 #include "base/strings/string_split.h"
+#include "base/strings/utf_string_conversions.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/base/resource/resource_bundle.h"
@@ -20,12 +21,6 @@ namespace {
 
 const int kTooltipHorizontalPadding = 3;
 
-// Max visual tooltip width. If a tooltip is greater than this width, it will
-// be wrapped.
-const int kTooltipMaxWidthPixels = 400;
-
-const size_t kMaxLines = 10;
-
 // TODO(derat): This padding is needed on Chrome OS devices but seems excessive
 // when running the same binary on a Linux workstation; presumably there's a
 // difference in font metrics.  Rationalize this.
@@ -55,6 +50,8 @@ views::Widget* CreateTooltipWidget(aura::Window* tooltip_window) {
 namespace views {
 namespace corewm {
 
+const int TooltipAura::kPreferredWidthPixels = 400;
+
 TooltipAura::TooltipAura(gfx::ScreenType screen_type)
     : screen_type_(screen_type),
       widget_(NULL),
@@ -69,93 +66,105 @@ TooltipAura::~TooltipAura() {
 
 // static
 void TooltipAura::TrimTooltipToFit(const gfx::FontList& font_list,

[sky, 2014/06/18 03:20:07]

I think we should convert this to use views::Label. It does all the wrapping and
should be a lot simpler.

[Daniel Erat, 2014/06/18 04:37:11]

i don't know the history here, but i believe that this text already goes into a
views::Label. presumably Label doesn't (or didn't?) do everything that's needed.
varun?

[varunjain, 2014/06/22 20:00:30]

Sorry I do not remember why label was not used directly. I have not worked on
this for along time now. I do remember that this function was copied from the
really old tooltip_manager so it might not be required. Other than that I have
no recollection of what/why this is.

-                                   int max_width,
+                                   const gfx::Size& max_size,
                                    base::string16* text,
                                    int* width,
                                    int* line_count) {
   *width = 0;
   *line_count = 0;
 
-  // Determine the available width for the tooltip.
-  int available_width = std::min(kTooltipMaxWidthPixels, max_width);
-
   std::vector<base::string16> lines;
   base::SplitString(*text, '\n', &lines);
-  std::vector<base::string16> result_lines;
+
+  // TODO: Use ICU to split into words.
+  int max_word_width = 0;
+  std::vector<std::vector<base::string16> > words_by_line;
+  for (size_t i = 0; i < lines.size(); ++i) {
+    std::vector<base::string16> words;
+    base::SplitStringDontTrim(lines[i], ' ', &words);
+    for (size_t j = 0; j < words.size(); ++j) {
+      const base::string16& word = words[j];
+      max_word_width = std::max(gfx::GetStringWidth(word, font_list),
+                                max_word_width);
+    }
+    words_by_line.push_back(words);
+  }
+
+  // Determine the available width for the tooltip.
+  const int available_width = std::min(max_size.width(),
+      std::max(max_word_width, kPreferredWidthPixels));
 
   // Format each line to fit.
-  for (std::vector<base::string16>::iterator l = lines.begin();
-       l != lines.end(); ++l) {
+  std::vector<base::string16> result_lines;
+  const base::string16 space(base::ASCIIToUTF16(" "));
+  for (size_t i = 0; i < words_by_line.size(); ++i) {
     // We break the line at word boundaries, then stuff as many words as we can
     // in the available width to the current line, and move the remaining words
     // to a new line.
-    std::vector<base::string16> words;
-    base::SplitStringDontTrim(*l, ' ', &words);
-    int current_width = 0;
+    const std::vector<base::string16>& words = words_by_line[i];
     base::string16 line;
-    for (std::vector<base::string16>::iterator w = words.begin();
-         w != words.end(); ++w) {
-      base::string16 word = *w;
-      if (w + 1 != words.end())
-        word.push_back(' ');
-      int word_width = gfx::GetStringWidth(word, font_list);
-      if (current_width + word_width > available_width) {
-        // Current width will exceed the available width. Must start a new line.
-        if (!line.empty())
-          result_lines.push_back(line);
-        current_width = 0;
-        line.clear();
+    for (size_t j = 0; j < words.size(); ++j) {
+      const base::string16& word = words[j];
+      if (!line.empty()) {
+        // Put the word on the end of the line if it fits.
+        base::string16 proposed_line = line + space + word;
+        if (gfx::GetStringWidth(proposed_line, font_list) <= available_width) {
+          line = proposed_line;
+          continue;
+        }
+        // Otherwise, save the in-progress line and start a new one.
+        result_lines.push_back(line);
       }
-      current_width += word_width;
-      line.append(word);
+      line = word;
     }
-    result_lines.push_back(line);
+    if (!line.empty())
+      result_lines.push_back(line);
   }
 
-  // Clamp number of lines to |kMaxLines|.
-  if (result_lines.size() > kMaxLines) {
-    result_lines.resize(kMaxLines);
+  // Clamp the number of lines.
+  const size_t max_lines = static_cast<size_t>(
+      std::max(1, max_size.height() / font_list.GetHeight()));
+  if (result_lines.size() > max_lines) {
+    result_lines.resize(max_lines);
     // Add ellipses character to last line.
-    result_lines[kMaxLines - 1] = gfx::TruncateString(
+    result_lines[max_lines - 1] = gfx::TruncateString(
         result_lines.back(), result_lines.back().length() - 1);
   }
   *line_count = result_lines.size();
 
   // Flatten the result.
   base::string16 result;
-  for (std::vector<base::string16>::iterator l = result_lines.begin();
-      l != result_lines.end(); ++l) {
+  for (size_t i = 0; i < result_lines.size(); ++i) {
     if (!result.empty())
       result.push_back('\n');
-    int line_width = gfx::GetStringWidth(*l, font_list);
+
+    base::string16 line = result_lines[i];
+    int line_width = gfx::GetStringWidth(line, font_list);
+
     // Since we only break at word boundaries, it could happen that due to some
     // very long word, line_width is greater than the available_width. In such
     // case, we simply truncate at available_width and add ellipses at the end.
     if (line_width > available_width) {
-      *width = available_width;
-      result.append(gfx::ElideText(*l, font_list, available_width,
-                                   gfx::ELIDE_TAIL));
-    } else {
-      *width = std::max(*width, line_width);
-      result.append(*l);
+      line = gfx::ElideText(line, font_list, available_width, gfx::ELIDE_TAIL);
+      line_width = gfx::GetStringWidth(line, font_list);
     }
+
+    result.append(line);
+    *width = std::max(*width, line_width);
   }
   *text = result;
 }
 
-int TooltipAura::GetMaxWidth(const gfx::Point& location) const {
-  // TODO(varunjain): implementation duplicated in tooltip_manager_aura. Figure
-  // out a way to merge.
+gfx::Size TooltipAura::GetMaxSize(const gfx::Point& location) const {
   gfx::Screen* screen = gfx::Screen::GetScreenByType(screen_type_);
   gfx::Rect display_bounds(screen->GetDisplayNearestPoint(location).bounds());
-  return (display_bounds.width() + 1) / 2;
+  return gfx::Size(display_bounds.width() * 3 / 4,

[sky, 2014/06/18 03:20:07]

I'm inclined to give the tooltip the full width. WDYT?

+                   display_bounds.height() * 3 / 4);
 }
 
 void TooltipAura::SetTooltipBounds(const gfx::Point& mouse_pos,
-                                   int tooltip_width,
-                                   int tooltip_height) {
-  gfx::Rect tooltip_rect(mouse_pos.x(), mouse_pos.y(), tooltip_width,
-                         tooltip_height);
+                                   const gfx::Size& tooltip_size) {
+  gfx::Rect tooltip_rect(mouse_pos, tooltip_size);
 
   tooltip_rect.Offset(kCursorOffsetX, kCursorOffsetY);
   gfx::Screen* screen = gfx::Screen::GetScreenByType(screen_type_);
@@ -171,7 +180,7 @@ void TooltipAura::SetTooltipBounds(const gfx::Point& mouse_pos,
   // If tooltip is out of bounds on the y axis, we flip it to appear above the
   // mouse cursor instead of below.
   if (tooltip_rect.bottom() > display_bounds.bottom())
-    tooltip_rect.set_y(mouse_pos.y() - tooltip_height);
+    tooltip_rect.set_y(mouse_pos.y() - tooltip_rect.height());
 
   tooltip_rect.AdjustToFit(display_bounds);
   widget_->SetBounds(tooltip_rect);
@@ -191,7 +200,7 @@ void TooltipAura::SetText(aura::Window* window,
   tooltip_window_ = window;
   int max_width, line_count;
   base::string16 trimmed_text(tooltip_text);
-  TrimTooltipToFit(label_.font_list(), GetMaxWidth(location), &trimmed_text,
+  TrimTooltipToFit(label_.font_list(), GetMaxSize(location), &trimmed_text,
                    &max_width, &line_count);
   label_.SetText(trimmed_text);
 
@@ -205,7 +214,7 @@ void TooltipAura::SetText(aura::Window* window,
     widget_->AddObserver(this);
   }
 
-  SetTooltipBounds(location, width, height);
+  SetTooltipBounds(location, gfx::Size(width, height));
 
   ui::NativeTheme* native_theme = widget_->GetNativeTheme();
   label_.set_background(