Golang图片操作：如何进行图片的渐变和纹理映射

package main

import (
    "image"
    "image/color"
    "image/png"
    "os"
)

// 渐变图片函数
func createGradient(width, height int) *image.RGBA {
    img := image.NewRGBA(image.Rect(0, 0, width, height))
    // 渐变色起始颜色和结束颜色
    startColor := color.RGBA{255, 0, 0, 255}    // 红色
    endColor := color.RGBA{0, 0, 255, 255}      // 蓝色

    // 计算每个像素的颜色并设置到图片上
    for y := 0; y < height; y++ {
        for x := 0; x < width; x++ {
            percent := float64(x) / float64(width-1)
            r := uint8(float64(startColor.R)*(1-percent) + float64(endColor.R)*percent)
            g := uint8(float64(startColor.G)*(1-percent) + float64(endColor.G)*percent)
            b := uint8(float64(startColor.B)*(1-percent) + float64(endColor.B)*percent)
            img.SetRGBA(x, y, color.RGBA{r, g, b, 255})
        }
    }
    return img
}

func main() {
    width, height := 640, 480
    img := createGradient(width, height)
    
    // 保存图片
    file, _ := os.Create("gradient.png")
    defer file.Close()
    png.Encode(file, img)
}

package main

import (
    "image"
    "image/color"
    "image/draw"
    "image/png"
    "os"
)

// 纹理映射函数
func applyTexture(targetImg draw.Image, textureImg image.Image, offsetX, offsetY int) {
    bounds := targetImg.Bounds()
    textureBounds := textureImg.Bounds()

    // 遍历目标图像的每个像素点，并根据纹理图像的坐标系获取对应的颜色值
    for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
        for x := bounds.Min.X; x < bounds.Max.X; x++ {
            textureX := (x-offsetX)%textureBounds.Dx()
            textureY := (y-offsetY)%textureBounds.Dy()
            textureColor := textureImg.At(textureX, textureY)
            targetImg.Set(x, y, textureColor)
        }
    }
}

func main() {
    targetImgFile, _ := os.Open("target.png")     // 目标图像文件
    targetImg, _ := png.Decode(targetImgFile)

    textureImgFile, _ := os.Open("texture.png")   // 纹理图像文件
    textureImg, _ := png.Decode(textureImgFile)

    offsetX, offsetY := 100, 100                  // 纹理映射的偏移值

    // 创建一个新的图像作为结果
    resultImg := image.NewRGBA(targetImg.Bounds())
    draw.Draw(resultImg, resultImg.Bounds(), targetImg, image.ZP, draw.Src)

    // 应用纹理映射
    applyTexture(resultImg, textureImg, offsetX, offsetY)

    // 保存结果图像
    resultFile, _ := os.Create("result.png")
    defer resultFile.Close()
    png.Encode(resultFile, resultImg)
}