monitor_reconfigure: Try to improve resolution selection.

src/platform/monitor_reconfig/monitor_reconfigure_main.cc

Index: src/platform/monitor_reconfig/monitor_reconfigure_main.cc
diff --git a/src/platform/monitor_reconfig/monitor_reconfigure_main.cc b/src/platform/monitor_reconfig/monitor_reconfigure_main.cc
index 52f30fa461e851b4d18e1573e5fb50396f910ff4..e0e07a3c2b51e3dbedd18297ab61436c7eff7249 100644
--- a/src/platform/monitor_reconfig/monitor_reconfigure_main.cc
+++ b/src/platform/monitor_reconfig/monitor_reconfigure_main.cc
@@ -4,19 +4,26 @@
 
 #include "monitor_reconfig/monitor_reconfigure_main.h"
 
+#include <algorithm>
 #include <cstdio>
 #include <cstdlib>
 
 #include "base/logging.h"
+#include "base/string_util.h"
 
 using std::map;
+using std::sort;
+using std::string;
+using std::vector;
 
 namespace monitor_reconfig {
 
 MonitorReconfigureMain::MonitorReconfigureMain(Display* display,
                                                XRRScreenResources* screen_info)
     : display_(display),
-      screen_info_(screen_info) {
+      screen_info_(screen_info),
+      lcd_output_(NULL),
+      external_output_(NULL) {
   for (int i = 0; i < screen_info_->nmode; ++i) {
     XRRModeInfo* current_mode = &screen_info_->modes[i];
     mode_map_[current_mode->id] = current_mode;
@@ -30,126 +37,131 @@ void MonitorReconfigureMain::DetermineOutputs() {
   XRROutputInfo* second_output =
       XRRGetOutputInfo(display_, screen_info_, screen_info_->outputs[1]);
 
-  static const char* kNotebookOutputName = "LVDS1";
-  if (strcmp(first_output->name, kNotebookOutputName) == 0) {
-    notebook_output_ = first_output;
+  static const char* kLcdOutputName = "LVDS1";
+  if (strcmp(first_output->name, kLcdOutputName) == 0) {
+    lcd_output_ = first_output;
     external_output_ = second_output;
   } else {
-    notebook_output_ = second_output;
+    lcd_output_ = second_output;
     external_output_ = first_output;
   }
 
-  for (int i = 0; i < notebook_output_->nmode; ++i) {
-    XRRModeInfo* mode = mode_map_[notebook_output_->modes[i]];
-    LOG(INFO) << "notebook mode: " << mode->width << "x" << mode->height;
+  LOG(INFO) << "LCD name: " << lcd_output_->name;
+  for (int i = 0; i < lcd_output_->nmode; ++i) {
+    XRRModeInfo* mode = mode_map_[lcd_output_->modes[i]];
+    LOG(INFO) << "  Mode: " << mode->width << "x" << mode->height;
   }
+
+  LOG(INFO) << "External name: " << external_output_->name;
   for (int i = 0; i < external_output_->nmode; ++i) {
     XRRModeInfo* mode = mode_map_[external_output_->modes[i]];
-    LOG(INFO) << "external mode: " << mode->width << "x" << mode->height;
+    LOG(INFO) << "  Mode: " << mode->width << "x" << mode->height;
   }
 }
 
-
-XRRModeInfo* MonitorReconfigureMain::FindMaxResolution(XRROutputInfo* output) {
-  XRRModeInfo* mode_return = NULL;
-  for (int i = 0; i < output->nmode; ++i) {
-    XRRModeInfo* current_mode = mode_map_[output->modes[i]];
-    if (mode_return == NULL) {
-      mode_return = current_mode;
-    } else {
-      int n_size = mode_return->height * mode_return->width;
-      int c_size = current_mode->height * current_mode->width;
-      if (c_size > n_size) {
-        mode_return = current_mode;
-      }
-    }
-  }
-  return mode_return;
-}
-
-bool MonitorReconfigureMain::IsEqual(XRRModeInfo* one, XRRModeInfo* two) {
-  return (one->height * one->width) == (two->height * two->width);
+bool MonitorReconfigureMain::IsExternalMonitorConnected() {
+  return (external_output_->connection == RR_Connected);
 }
 
-bool MonitorReconfigureMain::IsBiggerOrEqual(XRRModeInfo* target,
-                                             XRRModeInfo* screen) {
-  return ((target->width >= screen->width) &&
-          (target->height >= screen->height));
+void MonitorReconfigureMain::SortModesByResolution(
+    const XRROutputInfo& output_info, vector<XRRModeInfo*>* modes_out) {
+  modes_out->clear();
+  for (int i = 0; i < output_info.nmode; ++i)
+    modes_out->push_back(mode_map_[output_info.modes[i]]);
+  sort(modes_out->begin(), modes_out->end(), ModeResolutionComparator());
 }
 
-bool MonitorReconfigureMain::IsBetterMatching(XRRModeInfo* target,
-                                              XRRModeInfo* to_match,
-                                              XRRModeInfo* previous_best) {
-  if (IsEqual(previous_best, to_match))
-    return false;
-  // If the current will have some of the display cut off
-  // and the new choice doesn't, choose the new one
-  if ((!IsBiggerOrEqual(previous_best, to_match)) &&
-      (IsBiggerOrEqual(target, to_match))) {
-    return true;
-  // If the current one isn't cropped and the new one would
-  // get cropped
-  } else if (IsBiggerOrEqual(previous_best, to_match) &&
-             !IsBiggerOrEqual(target, to_match)) {
-    return false;
-  // Case if the current is bigger than the matching but the new target falls
-  // between the current and the matching (so it's closer to the matching)
-  } else if (IsBiggerOrEqual(previous_best, to_match)) {
-    return !IsBiggerOrEqual(target, previous_best);
+bool MonitorReconfigureMain::FindBestResolutions(
+    string* lcd_resolution,
+    string* external_resolution,
+    string* screen_resolution) {
+  DCHECK(lcd_resolution);
+  DCHECK(external_resolution);
+  DCHECK(screen_resolution);
+
+  vector<XRRModeInfo*> lcd_modes, external_modes;
+  SortModesByResolution(*lcd_output_, &lcd_modes);
+  SortModesByResolution(*external_output_, &external_modes);
+  DCHECK(!lcd_modes.empty());
+  DCHECK(!external_modes.empty());
+
+  if ((lcd_modes[0]->width * lcd_modes[0]->height) >=
+      (external_modes[0]->width * external_modes[0]->height)) {
+    return FindNearestResolutions(
+        lcd_modes, external_modes,
+        lcd_resolution, external_resolution, screen_resolution);
   } else {
-    // Final case, we know the current is smaller than the matching
-    // We just need to check if the new will bring us closer to the matching
-    return IsBiggerOrEqual(target, previous_best);
+    return FindNearestResolutions(
+        external_modes, lcd_modes,
+        external_resolution, lcd_resolution, screen_resolution);
   }
 }
 
-XRRModeInfo* MonitorReconfigureMain::FindBestMatchingResolution(
-    XRRModeInfo* matching_mode) {
-  // Need a min mode to increase from
-  XRRModeInfo min_mode;
-  min_mode.height = 0;
-  min_mode.width = 0;
-  XRRModeInfo* best_mode = &min_mode;
-  // Match horizontal if notebook is wider, o/w match vertical
-  for (int i = 0; i < external_output_->nmode; ++i) {
-    XRRModeInfo* current_mode = mode_map_[external_output_->modes[i]];
-    if (IsBetterMatching(current_mode, matching_mode, best_mode))
-      best_mode = current_mode;
+bool MonitorReconfigureMain::FindNearestResolutions(
+    const vector<XRRModeInfo*>& larger_device_modes,
+    const vector<XRRModeInfo*>& smaller_device_modes,
+    string* larger_resolution,
+    string* smaller_resolution,
+    string* screen_resolution) {
+  DCHECK(larger_resolution);
+  DCHECK(smaller_resolution);
+
+  // Start with the best that the smaller device has to offer.
+  smaller_resolution->assign(smaller_device_modes[0]->name);
+  *screen_resolution = *smaller_resolution;
+  int smaller_width = smaller_device_modes[0]->width;
+  int smaller_height = smaller_device_modes[0]->height;
+
+  for (vector<XRRModeInfo*>::const_reverse_iterator it =
+           larger_device_modes.rbegin();
+       it != larger_device_modes.rend(); ++it) {
+    if ((*it)->width >= smaller_width && (*it)->height >= smaller_height) {
+      larger_resolution->assign((*it)->name);
+      return true;
+    }
   }
-  if (best_mode == &min_mode)
-    best_mode = NULL;
-  return best_mode;
+
+  LOG(WARNING) << "Failed to find a resolution from larger device "
+               << "exceeding chosen resolution from smaller device ("
+               << *smaller_resolution << ")";
+  return false;
 }
 
-void MonitorReconfigureMain::SetResolutions(XRRModeInfo* notebook_mode,
-                                            XRRModeInfo* external_mode,
-                                            XRRModeInfo* overall_screen_size) {
-  // We use xrandr script to set modes
-  char buffer[512];
-  snprintf(buffer, sizeof(buffer), "xrandr --output %s --mode %s",
-           external_output_->name, external_mode->name);
-  system(buffer);
-  snprintf(buffer, sizeof(buffer), "xrandr --output %s --mode %s",
-           notebook_output_->name, notebook_mode->name);
-  system(buffer);
-  snprintf(buffer, sizeof(buffer), "xrandr --fb %s", overall_screen_size->name);
-  system(buffer);
+bool MonitorReconfigureMain::SetDeviceResolution(
+    const std::string& device_name, const std::string& resolution) {
+  string command = StringPrintf("xrandr --output %s --mode %s",
+                                device_name.c_str(), resolution.c_str());
+  LOG(INFO) << "Running " << command.c_str();
+  return system(command.c_str()) == 0;
+}
+
+bool MonitorReconfigureMain::SetScreenResolution(
+    const std::string& resolution) {
+  string command = StringPrintf("xrandr --fb %s", resolution.c_str());
+  LOG(INFO) << "Running " << command.c_str();
+  return system(command.c_str()) == 0;
 }
 
 void MonitorReconfigureMain::Run() {
-  if (!IsExternalMonitorConnected())
+  // If there's no external monitor connected, just use the highest resolution
+  // supported by the LCD.
+  if (!IsExternalMonitorConnected()) {
+    LOG(INFO) << "No external monitor connected; using max LCD resolution";
+    vector<XRRModeInfo*> lcd_modes;
+    SortModesByResolution(*lcd_output_, &lcd_modes);
+    CHECK(!lcd_modes.empty());
+    SetDeviceResolution(lcd_output_->name, lcd_modes[0]->name);
+    SetScreenResolution(lcd_modes[0]->name);
     return;
+  }
 
-  // Find the max resolution for the notebook
-  XRRModeInfo* notebook_mode = FindMaxResolution(notebook_output_);
-  // Find the best mode for external output relative to above mode
-  XRRModeInfo* external_mode = FindBestMatchingResolution(notebook_mode);
-  // Set the resolutions accordingly
-  SetResolutions(notebook_mode, external_mode, notebook_mode);
-}
-
-bool MonitorReconfigureMain::IsExternalMonitorConnected() {
-  return (external_output_->connection == RR_Connected);
+  string lcd_resolution, external_resolution, screen_resolution;
+  CHECK(FindBestResolutions(&lcd_resolution,
+                            &external_resolution,
+                            &screen_resolution));
+  SetDeviceResolution(lcd_output_->name, lcd_resolution);
+  SetDeviceResolution(external_output_->name, external_resolution);
+  SetScreenResolution(screen_resolution);
 }
 
 }  // end namespace monitor_reconfig