zorldo

Goofing around with Ebiten
git clone git://bsandro.tech/zorldo
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colorm.go (3730B)

      1 // Copyright 2014 Hajime Hoshi
      2 //
      3 // Licensed under the Apache License, Version 2.0 (the "License");
      4 // you may not use this file except in compliance with the License.
      5 // You may obtain a copy of the License at
      6 //
      7 //     http://www.apache.org/licenses/LICENSE-2.0
      8 //
      9 // Unless required by applicable law or agreed to in writing, software
     10 // distributed under the License is distributed on an "AS IS" BASIS,
     11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     12 // See the License for the specific language governing permissions and
     13 // limitations under the License.
     14 
     15 package ebiten
     16 
     17 import (
     18 	"image/color"
     19 
     20 	"github.com/hajimehoshi/ebiten/v2/internal/affine"
     21 )
     22 
     23 // ColorMDim is a dimension of a ColorM.
     24 const ColorMDim = affine.ColorMDim
     25 
     26 // A ColorM represents a matrix to transform coloring when rendering an image.
     27 //
     28 // A ColorM is applied to the straight alpha color
     29 // while an Image's pixels' format is alpha premultiplied.
     30 // Before applying a matrix, a color is un-multiplied, and after applying the matrix,
     31 // the color is multiplied again.
     32 //
     33 // The initial value is identity.
     34 type ColorM struct {
     35 	impl affine.ColorM
     36 
     37 	_ [0]func() // Marks as non-comparable.
     38 }
     39 
     40 func (c *ColorM) affineColorM() affine.ColorM {
     41 	if c.impl != nil {
     42 		return c.impl
     43 	}
     44 	return affine.ColorMIdentity{}
     45 }
     46 
     47 // String returns a string representation of ColorM.
     48 func (c *ColorM) String() string {
     49 	return affine.ColorMString(c.affineColorM())
     50 }
     51 
     52 // Reset resets the ColorM as identity.
     53 func (c *ColorM) Reset() {
     54 	c.impl = affine.ColorMIdentity{}
     55 }
     56 
     57 // Apply pre-multiplies a vector (r, g, b, a, 1) by the matrix
     58 // where r, g, b, and a are clr's values in straight-alpha format.
     59 // In other words, Apply calculates ColorM * (r, g, b, a, 1)^T.
     60 func (c *ColorM) Apply(clr color.Color) color.Color {
     61 	return c.affineColorM().Apply(clr)
     62 }
     63 
     64 // Concat multiplies a color matrix with the other color matrix.
     65 // This is same as muptiplying the matrix other and the matrix c in this order.
     66 func (c *ColorM) Concat(other ColorM) {
     67 	o := other.impl
     68 	if o == nil {
     69 		return
     70 	}
     71 	c.impl = c.affineColorM().Concat(o)
     72 }
     73 
     74 // Scale scales the matrix by (r, g, b, a).
     75 func (c *ColorM) Scale(r, g, b, a float64) {
     76 	c.impl = c.affineColorM().Scale(float32(r), float32(g), float32(b), float32(a))
     77 }
     78 
     79 // Translate translates the matrix by (r, g, b, a).
     80 func (c *ColorM) Translate(r, g, b, a float64) {
     81 	c.impl = c.affineColorM().Translate(float32(r), float32(g), float32(b), float32(a))
     82 }
     83 
     84 // RotateHue rotates the hue.
     85 // theta represents rotating angle in radian.
     86 func (c *ColorM) RotateHue(theta float64) {
     87 	c.ChangeHSV(theta, 1, 1)
     88 }
     89 
     90 // ChangeHSV changes HSV (Hue-Saturation-Value) values.
     91 // hueTheta is a radian value to rotate hue.
     92 // saturationScale is a value to scale saturation.
     93 // valueScale is a value to scale value (a.k.a. brightness).
     94 //
     95 // This conversion uses RGB to/from YCrCb conversion.
     96 func (c *ColorM) ChangeHSV(hueTheta float64, saturationScale float64, valueScale float64) {
     97 	c.impl = affine.ChangeHSV(c.affineColorM(), hueTheta, float32(saturationScale), float32(valueScale))
     98 }
     99 
    100 // Element returns a value of a matrix at (i, j).
    101 func (c *ColorM) Element(i, j int) float64 {
    102 	return float64(c.affineColorM().At(i, j))
    103 }
    104 
    105 // SetElement sets an element at (i, j).
    106 func (c *ColorM) SetElement(i, j int, element float64) {
    107 	c.impl = affine.ColorMSetElement(c.affineColorM(), i, j, float32(element))
    108 }
    109 
    110 // IsInvertible returns a boolean value indicating
    111 // whether the matrix c is invertible or not.
    112 func (c *ColorM) IsInvertible() bool {
    113 	return c.affineColorM().IsInvertible()
    114 }
    115 
    116 // Invert inverts the matrix.
    117 // If c is not invertible, Invert panics.
    118 func (c *ColorM) Invert() {
    119 	c.impl = c.affineColorM().Invert()
    120 }