ebiten/colorm.go

// Copyright 2014 Hajime Hoshi
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package ebiten

import (
	"github.com/hajimehoshi/ebiten/internal/affine"
)

// ColorMDim is a dimension of a ColorM.
const ColorMDim = affine.ColorMDim

// A ColorM represents a matrix to transform coloring when rendering an image.
//
// A ColorM is applied to the source alpha color
// while an Image's pixels' format is alpha premultiplied.
// Before applying a matrix, a color is un-multiplied, and after applying the matrix,
// the color is multiplied again.
//
// The initial value is identity.
type ColorM struct {
	impl affine.ColorM
}

// Concat multiplies a color matrix with the other color matrix.
// This is same as muptiplying the matrix other and the matrix c in this order.
func (c *ColorM) Concat(other ColorM) {
	c.impl.Concat(&other.impl)
}

// Add is deprecated as of 1.5.0-alpha.
// Note that this doesn't make sense as an operation for affine matrices.
func (c *ColorM) Add(other ColorM) {
	c.impl.Add(other.impl)
}

// Scale scales the matrix by (r, g, b, a).
func (c *ColorM) Scale(r, g, b, a float64) {
	c.impl.Scale(r, g, b, a)
}

// Translate translates the matrix by (r, g, b, a).
func (c *ColorM) Translate(r, g, b, a float64) {
	c.impl.Translate(r, g, b, a)
}

// RotateHue rotates the hue.
func (c *ColorM) RotateHue(theta float64) {
	c.impl.RotateHue(theta)
}

// ChangeHSV changes HSV (Hue-Saturation-Value) values.
// hueTheta is a radian value to ratate hue.
// saturationScale is a value to scale saturation.
// valueScale is a value to scale value (a.k.a. brightness).
//
// This conversion uses RGB to/from YCrCb conversion.
func (c *ColorM) ChangeHSV(hueTheta float64, saturationScale float64, valueScale float64) {
	c.impl.ChangeHSV(hueTheta, saturationScale, valueScale)
}

// Element returns a value of a matrix at (i, j).
func (c *ColorM) Element(i, j int) float64 {
	return c.impl.UnsafeElements()[i*affine.ColorMDim+j]
}

// SetElement sets an element at (i, j).
func (c *ColorM) SetElement(i, j int, value float64) {
	c.impl.SetElement(i, j, value)
}

// Monochrome returns a color matrix to make an image monochrome.
func Monochrome() ColorM {
	return ColorM{affine.Monochrome()}
}

// ScaleColor is deprecated as of 1.2.0-alpha. Use Scale instead.
func ScaleColor(r, g, b, a float64) ColorM {
	return ColorM{affine.ScaleColor(r, g, b, a)}
}

// TranslateColor is deprecated as of 1.2.0-alpha. Use Translate instead.
func TranslateColor(r, g, b, a float64) ColorM {
	return ColorM{affine.TranslateColor(r, g, b, a)}
}

// RotateHue is deprecated as of 1.2.0-alpha. Use RotateHue member function instead.
func RotateHue(theta float64) ColorM {
	return ColorM{affine.RotateHue(theta)}
}