Bug 1689682 - Include the desktop-to-device scaling factor in SizeConstraints r=mac-reviewers,mstange

Include the scaling factor in the SizeConstraints struct so that widgets can
correctly constrain their width and height when the widget's scaling factor
differs from the nsPresContext.

Differential Revision: https://phabricator.services.mozilla.com/D109265

layout/generic/nsContainerFrame.cpp

@@ -830,7 +830,13 @@ void nsContainerFrame::SetSizeConstraints(nsPresContext* aPresContext,
   if (devMinSize.height > devMaxSize.height)
     devMaxSize.height = devMinSize.height;
 
-  widget::SizeConstraints constraints(devMinSize, devMaxSize);
+  nsIWidget* rootWidget = aPresContext->GetNearestWidget();
+  DesktopToLayoutDeviceScale constraintsScale(MOZ_WIDGET_INVALID_SCALE);
+  if (rootWidget) {
+    constraintsScale = rootWidget->GetDesktopToDeviceScale();
+  }
+
+  widget::SizeConstraints constraints(devMinSize, devMaxSize, constraintsScale);
 
   // The sizes are in inner window sizes, so convert them into outer window
   // sizes. Use a size of (200, 200) as only the difference between the inner

widget/cocoa/nsCocoaWindow.mm

@@ -1140,29 +1140,32 @@ void nsCocoaWindow::SetSizeConstraints(const SizeConstraints& aConstraints) {
   NSRect rect = (mWindowType == eWindowType_popup) ? NSZeroRect : NSMakeRect(0.0, 0.0, 32, 32);
   rect = [mWindow frameRectForChildViewRect:rect];
 
-  CGFloat scaleFactor = BackingScaleFactor();
-
   SizeConstraints c = aConstraints;
-  c.mMinSize.width = std::max(nsCocoaUtils::CocoaPointsToDevPixels(rect.size.width, scaleFactor),
-                              c.mMinSize.width);
-  c.mMinSize.height = std::max(nsCocoaUtils::CocoaPointsToDevPixels(rect.size.height, scaleFactor),
-                               c.mMinSize.height);
 
-  NSSize minSize = {nsCocoaUtils::DevPixelsToCocoaPoints(c.mMinSize.width, scaleFactor),
-                    nsCocoaUtils::DevPixelsToCocoaPoints(c.mMinSize.height, scaleFactor)};
+  if (c.mScale.scale == MOZ_WIDGET_INVALID_SCALE) {
+    c.mScale.scale = BackingScaleFactor();
+  }
+
+  c.mMinSize.width = std::max(nsCocoaUtils::CocoaPointsToDevPixels(rect.size.width, c.mScale.scale),
+                              c.mMinSize.width);
+  c.mMinSize.height = std::max(
+      nsCocoaUtils::CocoaPointsToDevPixels(rect.size.height, c.mScale.scale), c.mMinSize.height);
+
+  NSSize minSize = {nsCocoaUtils::DevPixelsToCocoaPoints(c.mMinSize.width, c.mScale.scale),
+                    nsCocoaUtils::DevPixelsToCocoaPoints(c.mMinSize.height, c.mScale.scale)};
   [mWindow setMinSize:minSize];
 
-  c.mMaxSize.width = std::max(nsCocoaUtils::CocoaPointsToDevPixels(c.mMaxSize.width, scaleFactor),
-                              c.mMaxSize.width);
-  c.mMaxSize.height = std::max(nsCocoaUtils::CocoaPointsToDevPixels(c.mMaxSize.height, scaleFactor),
-                               c.mMaxSize.height);
+  c.mMaxSize.width = std::max(
+      nsCocoaUtils::CocoaPointsToDevPixels(c.mMaxSize.width, c.mScale.scale), c.mMaxSize.width);
+  c.mMaxSize.height = std::max(
+      nsCocoaUtils::CocoaPointsToDevPixels(c.mMaxSize.height, c.mScale.scale), c.mMaxSize.height);
 
   NSSize maxSize = {c.mMaxSize.width == NS_MAXSIZE
                         ? FLT_MAX
-                        : nsCocoaUtils::DevPixelsToCocoaPoints(c.mMaxSize.width, scaleFactor),
+                        : nsCocoaUtils::DevPixelsToCocoaPoints(c.mMaxSize.width, c.mScale.scale),
                     c.mMaxSize.height == NS_MAXSIZE
                         ? FLT_MAX
-                        : nsCocoaUtils::DevPixelsToCocoaPoints(c.mMaxSize.height, scaleFactor)};
+                        : nsCocoaUtils::DevPixelsToCocoaPoints(c.mMaxSize.height, c.mScale.scale)};
   [mWindow setMaxSize:maxSize];
 
   nsBaseWidget::SetSizeConstraints(c);
@@ -1677,12 +1680,19 @@ void nsCocoaWindow::DoResize(double aX, double aY, double aWidth, double aHeight
   AutoRestore<bool> reentrantResizeGuard(mInResize);
   mInResize = true;
 
-  // ConstrainSize operates in device pixels, so we need to convert using
-  // the backing scale factor here
-  CGFloat scale = BackingScaleFactor();
+  CGFloat scale = mSizeConstraints.mScale.scale;
+  if (scale == MOZ_WIDGET_INVALID_SCALE) {
+    scale = BackingScaleFactor();
+  }
+
+  // mSizeConstraints is in device pixels.
   int32_t width = NSToIntRound(aWidth * scale);
   int32_t height = NSToIntRound(aHeight * scale);
-  ConstrainSize(&width, &height);
+
+  width =
+      std::max(mSizeConstraints.mMinSize.width, std::min(mSizeConstraints.mMaxSize.width, width));
+  height = std::max(mSizeConstraints.mMinSize.height,
+                    std::min(mSizeConstraints.mMaxSize.height, height));
 
   DesktopIntRect newBounds(NSToIntRound(aX), NSToIntRound(aY), NSToIntRound(width / scale),
                            NSToIntRound(height / scale));
@@ -1831,21 +1841,6 @@ void nsCocoaWindow::BackingScaleFactorChanged() {
     return;
   }
 
-  if (mBackingScaleFactor > 0.0) {
-    // convert size constraints to the new device pixel coordinate space
-    double scaleFactor = newScale / mBackingScaleFactor;
-    mSizeConstraints.mMinSize.width = NSToIntRound(mSizeConstraints.mMinSize.width * scaleFactor);
-    mSizeConstraints.mMinSize.height = NSToIntRound(mSizeConstraints.mMinSize.height * scaleFactor);
-    if (mSizeConstraints.mMaxSize.width < NS_MAXSIZE) {
-      mSizeConstraints.mMaxSize.width =
-          std::min(NS_MAXSIZE, NSToIntRound(mSizeConstraints.mMaxSize.width * scaleFactor));
-    }
-    if (mSizeConstraints.mMaxSize.height < NS_MAXSIZE) {
-      mSizeConstraints.mMaxSize.height =
-          std::min(NS_MAXSIZE, NSToIntRound(mSizeConstraints.mMaxSize.height * scaleFactor));
-    }
-  }
-
   mBackingScaleFactor = newScale;
 
   if (!mWidgetListener || mWidgetListener->GetAppWindow()) {

widget/nsIWidget.h

@@ -172,6 +172,7 @@ typedef void* nsNativeWidget;
 #endif
 
 #define MOZ_WIDGET_MAX_SIZE 16384
+#define MOZ_WIDGET_INVALID_SCALE 0.0
 
 // Must be kept in sync with xpcom/rust/xpcom/src/interfaces/nonidl.rs
 #define NS_IWIDGET_IID                               \
@@ -293,11 +294,14 @@ namespace widget {
  * Values are in device pixels.
  */
 struct SizeConstraints {
-  SizeConstraints() : mMaxSize(MOZ_WIDGET_MAX_SIZE, MOZ_WIDGET_MAX_SIZE) {}
+  SizeConstraints()
+      : mMaxSize(MOZ_WIDGET_MAX_SIZE, MOZ_WIDGET_MAX_SIZE),
+        mScale(MOZ_WIDGET_INVALID_SCALE) {}
 
   SizeConstraints(mozilla::LayoutDeviceIntSize aMinSize,
-                  mozilla::LayoutDeviceIntSize aMaxSize)
-      : mMinSize(aMinSize), mMaxSize(aMaxSize) {
+                  mozilla::LayoutDeviceIntSize aMaxSize,
+                  mozilla::DesktopToLayoutDeviceScale aScale)
+      : mMinSize(aMinSize), mMaxSize(aMaxSize), mScale(aScale) {
     if (mMaxSize.width > MOZ_WIDGET_MAX_SIZE) {
       mMaxSize.width = MOZ_WIDGET_MAX_SIZE;
     }
@@ -308,6 +312,16 @@ struct SizeConstraints {
 
   mozilla::LayoutDeviceIntSize mMinSize;
   mozilla::LayoutDeviceIntSize mMaxSize;
+
+  /*
+   * The scale used to convert from desktop to device dimensions.
+   * MOZ_WIDGET_INVALID_SCALE if the value is not known.
+   *
+   * Bug 1701109 is filed to revisit adding of 'mScale' and deal
+   * with multi-monitor scaling issues in more complete way across
+   * all widget implementations.
+   */
+  mozilla::DesktopToLayoutDeviceScale mScale;
 };
 
 struct AutoObserverNotifier {