package artist import "image" import "git.tebibyte.media/sashakoshka/tomo/canvas" // Paste transfers one canvas onto another, offset by the specified point. func Paste ( destination canvas.Canvas, source canvas.Canvas, offset image.Point, ) ( updatedRegion image.Rectangle, ) { dstData, dstStride := destination.Buffer() srcData, srcStride := source.Buffer() sourceBounds := source.Bounds().Canon(). Intersect(destination.Bounds().Sub(offset)) if sourceBounds.Empty() { return } updatedRegion = sourceBounds.Add(offset) for y := sourceBounds.Min.Y; y < sourceBounds.Max.Y; y ++ { for x := sourceBounds.Min.X; x < sourceBounds.Max.X; x ++ { dstData[x + offset.X + (y + offset.Y) * dstStride] = srcData[x + y * srcStride] }} return } // FillRectangle draws a filled rectangle with the specified pattern. func FillRectangle ( destination canvas.Canvas, source Pattern, bounds image.Rectangle, ) ( updatedRegion image.Rectangle, ) { data, stride := destination.Buffer() realBounds := bounds bounds = bounds.Canon().Intersect(destination.Bounds()).Canon() if bounds.Empty() { return } updatedRegion = bounds realWidth, realHeight := realBounds.Dx(), realBounds.Dy() patternOffset := realBounds.Min.Sub(bounds.Min) width, height := bounds.Dx(), bounds.Dy() for y := 0; y < height; y ++ { for x := 0; x < width; x ++ { data[x + bounds.Min.X + (y + bounds.Min.Y) * stride] = source.AtWhen ( x - patternOffset.X, y - patternOffset.Y, realWidth, realHeight) }} return } // StrokeRectangle draws the outline of a rectangle with the specified line // weight and pattern. func StrokeRectangle ( destination canvas.Canvas, source Pattern, weight int, bounds image.Rectangle, ) { bounds = bounds.Canon() insetBounds := bounds.Inset(weight) if insetBounds.Empty() { FillRectangle(destination, source, bounds) return } // top FillRectangle (destination, source, image.Rect ( bounds.Min.X, bounds.Min.Y, bounds.Max.X, insetBounds.Min.Y)) // bottom FillRectangle (destination, source, image.Rect ( bounds.Min.X, insetBounds.Max.Y, bounds.Max.X, bounds.Max.Y)) // left FillRectangle (destination, source, image.Rect ( bounds.Min.X, insetBounds.Min.Y, insetBounds.Min.X, insetBounds.Max.Y)) // right FillRectangle (destination, source, image.Rect ( insetBounds.Max.X, insetBounds.Min.Y, bounds.Max.X, insetBounds.Max.Y)) }