Summary
Safe Zone preview bars disappear in editor when clicking on the “Flip Safe Zone” button. This is because slate silently fail to render rectangles with a negative size
The fix is to flip the rectangle taking into account the width and the orientation or slate won’t render rectangles with a negative width
What Type of Bug are you experiencing?
Editor
Steps to Reproduce
Open any UMG Widget Blueprint or create a new one. Then from the Screen Size drop down select any mobile device that has safezones defined in their profile.
Press the Flip The Current Safe Zones button on the left of the drop down
Expected Result
The red bars representing the safezones defined for the phone should flip
Observed Result
The red bars disappear. They reappear if you flip them again.
Affects Versions
5.8
5.7
5.6
5.5
5.4
Platform(s)
Windows
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Additional Notes
This is the fixed code for “SettingsClasses.cpp”
FMargin ULevelEditorPlaySettings::FlipCustomUnsafeZones(TArray<FVector2D>& CustomSafeZoneStarts, TArray<FVector2D>& CustomSafeZoneDimensions, FString& DeviceType, FVector2D PreviewSize)
{
FMargin CustomSafeZoneOverride = CalculateCustomUnsafeZones(CustomSafeZoneStarts, CustomSafeZoneDimensions, DeviceType, PreviewSize);
// FIX BEGIN - Mirror each zone rect as a whole
// to prevent producing negative-width rectangles that Slate silently refuses to draw
for (int32 ZoneIndex = 0; ZoneIndex < CustomSafeZoneStarts.Num(); ++ZoneIndex)
{
CustomSafeZoneStarts[ZoneIndex].X = PreviewSize.X - CustomSafeZoneStarts[ZoneIndex].X - CustomSafeZoneDimensions[ZoneIndex].X;
}
// FIX END - Mirror each zone rect as a whole
// to prevent producing negative-width rectangles that Slate silently refuses to draw
float Placeholder = CustomSafeZoneOverride.Left;
CustomSafeZoneOverride.Left = CustomSafeZoneOverride.Right;
CustomSafeZoneOverride.Right = Placeholder;
return CustomSafeZoneOverride;
}