Allow arbitrary scale factors.

As discussed in https://codereview.chromium.org/1070433002/, this CL allows arbitrary scale factors, which works because chromium uses the resource most closely matching the scale factor (e.g. 1x for 1.25x, but 2x for 1.9x) and scales it. BUG=143619,477716 Review URL: https://codereview.chromium.org/1078423002 Cr-Commit-Position: refs/heads/master@{#326851} (cherry picked from commit b3ca230) device scale factor detection: use gtk-xft-dpi consistently Before this CL, we used either gtk-xft-dpi (UI fonts) or the physical DPI of a more or less random display. This CL consistently uses gtk-xft-dpi which is the better alternative: users can directly influence it (by changing the Xft.dpi X resource, or via their gtkrc). See also https://github.com/derat/font-config-info for displaying your current system settings. This is a re-do of https://codereview.chromium.org/1070433002/, but with https://codereview.chromium.org/1084453002/ applied (fixes content_shell). BUG=473089, 143619 Review URL: https://codereview.chromium.org/1085603002 Cr-Commit-Position: refs/heads/master@{#324928} (cherry picked from commit d459a5c) [email protected] TBR=erg, estade, oshima Review URL: https://codereview.chromium.org/1103383004 Cr-Commit-Position: refs/branch-heads/2357@{#246} Cr-Branched-From: 59d4494-refs/heads/master@{#323860}
crosswalk-project · Apr 28, 2015 · 7cec497 · 7cec497
1 parent 95d620a
commit 7cec497
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diff --git a/chrome/browser/ui/libgtk2ui/gtk2_ui.cc b/chrome/browser/ui/libgtk2ui/gtk2_ui.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/ui/libgtk2ui/gtk2_ui.h"
 
+#include <math.h>
 #include <set>
 
 #include <pango/pango.h>
@@ -380,16 +381,20 @@ gfx::FontRenderParams GetGtkFontRenderParams() {
   return params;
 }
 
-// Queries GTK for its font DPI setting and returns the number of pixels in a
-// point.
-double GetPixelsInPoint(float device_scale_factor) {
+double GetDPI() {
   GtkSettings* gtk_settings = gtk_settings_get_default();
   CHECK(gtk_settings);
   gint gtk_dpi = -1;
   g_object_get(gtk_settings, "gtk-xft-dpi", &gtk_dpi, NULL);
 
   // GTK multiplies the DPI by 1024 before storing it.
-  double dpi = (gtk_dpi > 0) ? gtk_dpi / 1024.0 : 96.0;
+  return (gtk_dpi > 0) ? gtk_dpi / 1024.0 : 96.0;
+}
+
+// Queries GTK for its font DPI setting and returns the number of pixels in a
+// point.
+double GetPixelsInPoint(float device_scale_factor) {
+  double dpi = GetDPI();
 
   // Take device_scale_factor into account — if Chrome already scales the
   // entire UI up by 2x, we should not also scale up.
@@ -1420,6 +1425,13 @@ void Gtk2UI::UpdateDeviceScaleFactor(float device_scale_factor) {
   UpdateDefaultFont(label_style->font_desc);
 }
 
+float Gtk2UI::GetDeviceScaleFactor() const {
+  const int kCSSDefaultDPI = 96;
+  float scale = GetDPI() / kCSSDefaultDPI;
+  // Round to 2 decimals, e.g. to 1.33.
+  return roundf(scale * 100) / 100;
+}
+
 }  // namespace libgtk2ui
 
 views::LinuxUI* BuildGtk2UI() {

diff --git a/chrome/browser/ui/libgtk2ui/gtk2_ui.h b/chrome/browser/ui/libgtk2ui/gtk2_ui.h
@@ -121,6 +121,7 @@ class Gtk2UI : public views::LinuxUI {
 
   // ui::Views::LinuxUI:
   void UpdateDeviceScaleFactor(float device_scale_factor) override;
+  float GetDeviceScaleFactor() const override;
 
  private:
   typedef std::map<int, SkColor> ColorMap;

diff --git a/testing/xvfb.py b/testing/xvfb.py
@@ -50,7 +50,7 @@ def start_xvfb(xvfb_path, display):
     xvfb_path: Path to Xvfb.
   """
   cmd = [xvfb_path, display, '-screen', '0', '1024x768x24', '-ac',
-         '-nolisten', 'tcp']
+         '-nolisten', 'tcp', '-dpi', '96']
   try:
     proc = subprocess.Popen(
         cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)

diff --git a/ui/views/linux_ui/linux_ui.h b/ui/views/linux_ui/linux_ui.h
@@ -154,6 +154,9 @@ class VIEWS_EXPORT LinuxUI : public ui::LinuxInputMethodContextFactory,
   // Updates the device scale factor so that the default font size can be
   // recalculated.
   virtual void UpdateDeviceScaleFactor(float device_scale_factor) = 0;
+
+  // Determines the device scale factor of the primary screen.
+  virtual float GetDeviceScaleFactor() const = 0;
 };
 
 }  // namespace views

diff --git a/ui/views/widget/desktop_aura/desktop_screen_x11.cc b/ui/views/widget/desktop_aura/desktop_screen_x11.cc
@@ -25,6 +25,7 @@
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/screen.h"
 #include "ui/gfx/x/x11_types.h"
+#include "ui/views/linux_ui/linux_ui.h"
 #include "ui/views/widget/desktop_aura/desktop_screen.h"
 #include "ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h"
 #include "ui/views/widget/desktop_aura/x11_topmost_window_finder.h"
@@ -35,21 +36,12 @@ namespace {
 // in |Dispatch()|.
 const int64 kConfigureDelayMs = 500;
 
-// TODO(oshima): Consider using gtk-xft-dpi instead.
-float GetDeviceScaleFactor(int screen_pixels, int screen_mm) {
-  const int kCSSDefaultDPI = 96;
-  const float kInchInMm = 25.4f;
-
-  float screen_inches = screen_mm / kInchInMm;
-  float screen_dpi = screen_pixels / screen_inches;
-  float scale = screen_dpi / kCSSDefaultDPI;
-
-  return ui::GetScaleForScaleFactor(ui::GetSupportedScaleFactor(scale));
-}
-
-float GetDeviceScaleFactor() {
-  gfx::Display display = gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
-  return display.device_scale_factor();
+double GetDeviceScaleFactor() {
+  float device_scale_factor = 1.0f;
+  if (views::LinuxUI::instance())
+    device_scale_factor =
+      views::LinuxUI::instance()->GetDeviceScaleFactor();
+  return device_scale_factor;
 }
 
 gfx::Point PixelToDIPPoint(const gfx::Point& pixel_point) {
@@ -71,8 +63,7 @@ std::vector<gfx::Display> GetFallbackDisplayList() {
   gfx::Display gfx_display(0, bounds_in_pixels);
   if (!gfx::Display::HasForceDeviceScaleFactor() &&
       !ui::IsDisplaySizeBlackListed(physical_size)) {
-    float device_scale_factor = GetDeviceScaleFactor(
-        width, physical_size.width());
+    const float device_scale_factor = GetDeviceScaleFactor();
     DCHECK_LE(1.0f, device_scale_factor);
     gfx_display.SetScaleAndBounds(device_scale_factor, bounds_in_pixels);
   }
@@ -294,7 +285,9 @@ std::vector<gfx::Display> DesktopScreenX11::BuildDisplaysFromXRandRInfo() {
     has_work_area = true;
   }
 
-  float device_scale_factor = 1.0f;
+  // As per-display scale factor is not supported right now,
+  // the X11 root window's scale factor is always used.
+  const float device_scale_factor = GetDeviceScaleFactor();
   for (int i = 0; i < resources->noutput; ++i) {
     RROutput output_id = resources->outputs[i];
     gfx::XScopedPtr<XRROutputInfo,
@@ -321,14 +314,6 @@ std::vector<gfx::Display> DesktopScreenX11::BuildDisplaysFromXRandRInfo() {
       gfx::Display display(display_id, crtc_bounds);
 
       if (!gfx::Display::HasForceDeviceScaleFactor()) {
-        if (i == 0 && !ui::IsDisplaySizeBlackListed(
-            gfx::Size(output_info->mm_width, output_info->mm_height))) {
-          // As per display scale factor is not supported right now,
-          // the primary display's scale factor is always used.
-          device_scale_factor = GetDeviceScaleFactor(crtc->width,
-                                                     output_info->mm_width);
-          DCHECK_LE(1.0f, device_scale_factor);
-        }
         display.SetScaleAndBounds(device_scale_factor, crtc_bounds);
       }