Question

I have this xaml

    <Image Width="240" Height="240">                
        <Image.Source>                    
            <DrawingImage>
                <DrawingImage.Drawing>
                    <DrawingGroup>
                        <DrawingGroup>
                            <DrawingGroup>
                                <DrawingGroup.Transform>
                                    <TransformGroup>
                                        <RotateTransform Angle="-15" CenterX="120" CenterY="120" />
                                        <TranslateTransform Y="-20" />
                                    </TransformGroup>
                                </DrawingGroup.Transform>

                                <ImageDrawing ImageSource="Images\pNxVK.png" Rect="0,0,240,240" />
                            </DrawingGroup>

                            <DrawingGroup.ClipGeometry>
                                <EllipseGeometry Center="120,120" RadiusX="60" RadiusY="60" />
                            </DrawingGroup.ClipGeometry>
                        </DrawingGroup>

                        <DrawingGroup>
                            <DrawingGroup>
                                <!--<DrawingGroup.Transform>
                                    <RotateTransform Angle="-15" CenterX="120" CenterY="120" />
                                </DrawingGroup.Transform>-->
                                <ImageDrawing ImageSource="Images\zUr8D.png" Rect="0,0,240,240" />
                            </DrawingGroup>                                        
                            <ImageDrawing ImageSource="Images\XPZW9.png" Rect="0,0,240,240" />
                        </DrawingGroup>                                
                    </DrawingGroup>
                </DrawingImage.Drawing>
            </DrawingImage>
        </Image.Source>
    </Image>

The result of that xaml is (Correct size)

If I uncomment the rotate transform in the xaml above i get this (Wrong size)

Answer 1

The drawings are rectangles. And a rotated rectangle has bigger bounding box than a non-rotated one, so it has to be scaled to fit the original boundaries.

You can resolve this by specifying ClipGeometry of the outermost DrawingGroup – just clip it to the original bounds.

<DrawingGroup.ClipGeometry>
    <RectangleGeometry Rect="0 0 240 240" />
</DrawingGroup.ClipGeometry>