Transformation and Composition

Transformation

All Drawable objects can do 2D transformation using Translate(), Scale() and Rotate() APIs. And it also provides an interface for matrix transformation using a 9-size (3x3 matrix) float type array.

                
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//generate a drawable group
DrawableGroup drawableGroup = new DrawableGroup();

//generate a round rectangle
Shape rect = new Shape();
rect.AddRect(-50.0f, -50.0f, 100.0f, 100.0f, 20.0f, 20.0f);
rect.FillColor = Color.Red;

//Add the rectangle into the drawable group
drawableGroup.AddDrawable(rect);

//generate a circle
Shape circle = new Shape();
circle.AddCircle(0.0f, 50.0f, 50.0f, 50.0f);
circle.FillColor = Color.Green;

//add the circle into the drawable group
drawableGroup.AddDrawable(circle);

//generate an ellipse
Shape ellipse = new Shape();
ellipse.AddCircle(0.0f, 0.0f, 50.0f, 50.0f);
ellipse.FillColor = Color.Blue;

//transform ellipse using matrix transformation
float[] matrix = new float[] {1.0f, 0.0f, 300.0f,
                              0.0f, 2.0f, 150.0f,
                              0.0f, 0.0f,  1.0f};
ellipse.Transform(matrix);

//add the ellipse into the canvas view
canvasView.AddDrawable(ellipse);

//transform DrawableGroup using transformation APIs
drawableGroup.Rotate(45.0f);
drawableGroup.Scale(1.3f);
drawableGroup.Translate(150.0f, 150.0f);

//add the drawable group into the canvas view
canvasView.AddDrawable(drawableGroup);

Composition

All Drawable can apply composition for visual effects such as alpha blending, masking(alpha/alpha inverse) and clipping.

Alpha blend

Alpha blending can be applied by adjusting the Opacity property of the Drawable object and the alpha values of FillColor and StrokeColor. Below is an example of alpha blending in various cases.

                
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//generate a drawable group
DrawableGroup drawableGroup = new DrawableGroup();

//generate a round rectangle
Shape rect = new Shape();
rect.AddRect(50.0f, 50.0f, 200.0f, 200.0f, 20.0f, 20.0f);
rect.FillColor = Color.Red;

//Add the rectangle into the drawable group
drawableGroup.AddDrawable(rect);

//generate a circle
Shape circle = new Shape();
circle.AddCircle(200.0f, 200.0f, 100.0f, 100.0f);
circle.FillColor = Color.Green;

//add the circle into the drawable group
drawableGroup.AddDrawable(circle);

//set opacity value
drawableGroup.Opacity = 0.5f;

//generate an ellipse
Shape ellipse = new Shape();

ellipse.AddCircle(180.0f, 100.0f, 120.0f, 60.0f);

//set ellipse translucent color
ellipse.FillColor = new Color(0.0f, 0.0f, 1.0f, 0.5f);

//add the ellipse into the canvas view
canvasView.AddDrawable(ellipse);

//add the drawable group into the canvas view
canvasView.AddDrawable(drawableGroup);

Clip Path

Clip path is a composition based on path information. The intersection with clip Drawable is determined and only the resulting pixels from own Drawable are rendered.

Below is an example of clipping.

                
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//generate two round rectangles
Shape rect = new Shape();
rect.AddRect(50.0f, 50.0f, 150.0f, 150.0f, 30.0f, 30.0f);
rect.AddRect(100.0f, 100.0f, 150.0f, 150.0f, 30.0f, 30.0f);
rect.FillColor = Color.Red;

//generate a picture
Picture picture = new Picture();
picture.Load( <IMAGE_FILE_PATH> );
picture.SetSize(new Size2D(400, 400));

//clipping picture to rect
picture.ClipPath(rect);

//add the rect into the canvas view
canvasView.AddDrawable(picture);

Mask

As for the MaskType, Alpha Mask and InverseAlpha Mask are provided.

Below is an example of masking.

                
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//generate two round rectangles
Shape rect = new Shape();
rect.AddRect(50.0f, 50.0f, 150.0f, 150.0f, 30.0f, 30.0f);
rect.AddRect(100.0f, 100.0f, 150.0f, 150.0f, 30.0f, 30.0f);
rect.FillColor = Color.Red;
rect.Opacity = 0.5f;

//generate a picture
Picture picture = new Picture();
picture.Load( <IMAGE_FILE_PATH> );
picture.SetSize(new Size2D(250, 250));

//alpha masking picture to rect
picture.Mask(rect, MaskType.Alpha);

//add the rect into the canvas view
canvasView.AddDrawable(picture);

//generate two round rectangles
Shape rect2 = new Shape();
rect2.AddRect(40.0f, 350.0f, 150.0f, 150.0f, 30.0f, 30.0f);
rect2.AddRect(100.0f, 400.0f, 150.0f, 150.0f, 30.0f, 30.0f);
rect2.FillColor = Color.Red;
rect2.Opacity = 0.5f;

//generate a picture
Picture picture2 = new Picture();
picture2.Load( <IMAGE_FILE_PATH> );
picture2.Translate(0.0f ,300.0f);
picture2.SetSize(new Size2D(250, 250));

//inverse alpha masking picture to rect
picture2.Mask(rect2, MaskType.AlphaInverse);

//add the rect into the canvas view
canvasView.AddDrawable(picture2);

Note

A composition may perform an additional render-processing on an off-screen buffer. The excessive usage of a composition may negatively affect processing speed.

Related information

• Dependencies
  • Tizen 6.5 and Higher