Refactoring Session: Sophisticated Image Handling

[ulikk]

PROBLEM: We want to maintain a dynamic set of input images for the painter, and these images can be arbitrarily sized. It should be possible to compose them in arbitrary position.

[ulikk]

My Proposal:

• The painter holds a list of input images and a image that corresponds to the drawing canvas
• Each input image is associated with a transformation
• For each input image, a transformed version is calculated that corresponds to the drawing canvas which will be used by the brushes for painting

The question is, how to we abstract this, and who holds which information.

[ulikk]

Proposal2:

• The "Image" Class purpose is solely for storing width and height and image data
• Transformation is done via an additional utility class ImageTransform (might be included directly in the image aswell)
• Transformation is done by an affine transformation represented by a 3x3 matrix,

transformed = ImageTransform.transform( image, matrix, width, height )

• The painter stores an Image for the painting canvas, and a list of images with associated transformations
• whenever a transformation changes, the transformed image is recalculated
• painting is carried out between the painting canvas and the transformed images
• A transformation can be manipulated by the following interface:

move( x, y )
scale( x, y, sx, sx )
rotate( x, y, angle )