93 lines
2.1 KiB
Go
93 lines
2.1 KiB
Go
package pixel
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import "image/color"
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// RGBA represents a alpha-premultiplied RGBA color with components within range [0, 1].
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//
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// The difference between color.RGBA is that the value range is [0, 1] and the values are floats.
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type RGBA struct {
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R, G, B, A float64
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}
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// Add adds color d to color c component-wise and returns the result (the components are not
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// clamped).
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func (c RGBA) Add(d RGBA) RGBA {
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return RGBA{
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R: c.R + d.R,
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G: c.G + d.G,
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B: c.B + d.B,
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A: c.A + d.A,
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}
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}
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// Sub subtracts color d from color c component-wise and returns the result (the components
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// are not clamped).
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func (c RGBA) Sub(d RGBA) RGBA {
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return RGBA{
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R: c.R - d.R,
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G: c.G - d.G,
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B: c.B - d.B,
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A: c.A - d.A,
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}
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}
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// Mul multiplies color c by color d component-wise (the components are not clamped).
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func (c RGBA) Mul(d RGBA) RGBA {
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return RGBA{
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R: c.R * d.R,
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G: c.G * d.G,
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B: c.B * d.B,
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A: c.A * d.A,
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}
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}
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// Scaled multiplies each component of color c by scale and returns the result (the components
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// are not clamped).
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func (c RGBA) Scaled(scale float64) RGBA {
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return RGBA{
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R: c.R * scale,
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G: c.G * scale,
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B: c.B * scale,
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A: c.A * scale,
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}
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}
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// RGBA returns alpha-premultiplied red, green, blue and alpha components of the RGBA color.
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func (c RGBA) RGBA() (r, g, b, a uint32) {
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r = uint32(0xffff * c.R)
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g = uint32(0xffff * c.G)
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b = uint32(0xffff * c.B)
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a = uint32(0xffff * c.A)
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return
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}
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// ToRGBA converts a color to RGBA format. Using this function is preferred to using RGBAModel, for
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// performance (using RGBAModel introduced additional unnecessary allocations).
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func ToRGBA(c color.Color) RGBA {
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if c, ok := c.(RGBA); ok {
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return c
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}
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if c, ok := c.(color.RGBA); ok {
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return RGBA{
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R: float64(c.R) / 255,
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G: float64(c.G) / 255,
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B: float64(c.B) / 255,
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A: float64(c.A) / 255,
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}
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}
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r, g, b, a := c.RGBA()
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return RGBA{
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float64(r) / 0xffff,
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float64(g) / 0xffff,
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float64(b) / 0xffff,
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float64(a) / 0xffff,
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}
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}
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// RGBAModel converts colors to RGBA format.
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var RGBAModel = color.ModelFunc(rgbaModel)
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func rgbaModel(c color.Color) color.Color {
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return ToRGBA(c)
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}
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