67 lines
2.1 KiB
Go
67 lines
2.1 KiB
Go
package artist
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import "image"
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import "git.tebibyte.media/sashakoshka/tomo/canvas"
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import "git.tebibyte.media/sashakoshka/tomo/shatter"
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// Pattern is capable of drawing to a canvas within the bounds of a given
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// clipping rectangle.
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type Pattern interface {
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// Draw draws to destination, using the bounds of destination as a width
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// and height for things like gradients, bevels, etc. The pattern may
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// not draw outside the union of destination.Bounds() and clip. The
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// clipping rectangle effectively takes a subset of the pattern. To
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// change the bounds of the pattern itself, use canvas.Cut() on the
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// destination before passing it to Draw().
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Draw (destination canvas.Canvas, clip image.Rectangle)
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}
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// Draw lets you use several clipping rectangles to draw a pattern.
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func Draw (
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destination canvas.Canvas,
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source Pattern,
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clips ...image.Rectangle,
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) (
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updatedRegion image.Rectangle,
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) {
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for _, clip := range clips {
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source.Draw(destination, clip)
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updatedRegion = updatedRegion.Union(clip)
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}
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return
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}
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// DrawBounds lets you specify an overall bounding rectangle for drawing a
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// pattern. The destination is cut to this rectangle.
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func DrawBounds (
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destination canvas.Canvas,
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source Pattern,
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bounds image.Rectangle,
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) (
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updatedRegion image.Rectangle,
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) {
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return Draw(canvas.Cut(destination, bounds), source, bounds)
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}
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// DrawShatter is like an inverse of Draw, drawing nothing in the areas
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// specified in "rocks".
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func DrawShatter (
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destination canvas.Canvas,
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source Pattern,
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rocks ...image.Rectangle,
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) (
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updatedRegion image.Rectangle,
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) {
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return Draw(destination, source, shatter.Shatter(destination.Bounds(), rocks...)...)
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}
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// AllocateSample returns a new canvas containing the result of a pattern. The
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// resulting canvas can be sourced from shape drawing functions. I beg of you
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// please do not call this every time you need to draw a shape with a pattern on
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// it because that is horrible and cruel to the computer.
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func AllocateSample (source Pattern, width, height int) (allocated canvas.Canvas) {
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allocated = canvas.NewBasicCanvas(width, height)
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source.Draw(allocated, allocated.Bounds())
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return
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}
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