unity中实现截取全屏的功能，还有压缩图片的功能

unity中实现截取全屏的功能

1、截屏方法如下：

/// <summary>
    /// 读取指定相机渲染的像素---本次使用的
    /// </summary>
    private void ScreenShot_ReadPixelsWithCamera(Camera _camera)
    {
    
    
        //对指定相机进行 RenderTexture
        RenderTexture renTex = new RenderTexture(Screen.width, Screen.height, 16);
        _camera.targetTexture = renTex;
        _camera.Render();
        RenderTexture.active = renTex;
        //读取像素，这句比较重要，如果不加TextureFormat.RGB24，截出来的图片就是很模糊的，里边很多像素点，需要多加注意
        Texture2D tex = new Texture2D(Screen.width, Screen.height, TextureFormat.RGB24, false);
        //读取图片像素
        tex.ReadPixels(new Rect(0, 0, tex.width, tex.height), 0, 0);
        tex.Apply();
        //压缩图片的功能---可以不需要
        tex = ScaleTexture(tex, tex.width / 3, tex.height / 3);
        PictureList.Add(tex);//这一步是我需要，存储了一下截屏的图片，可以省去
        MyRectTransform.GetComponent<Image>().sprite = ToSprite(tex);
        //读取目标相机像素结束，渲染恢复原先的方式
        _camera.targetTexture = null;
        RenderTexture.active = null;
        Destroy(renTex);
    }

2、 将texture转换为sprite

 /// <summary>
    /// 将texture转换为sprite
    /// </summary>
    /// <param name="self"></param>
    /// <returns></returns>
    public Sprite ToSprite(Texture2D self)
    {
    
    
        var rect = new Rect(0, 0, self.width, self.height);
        var pivot = Vector2.one * 0.5f;
        var newSprite = Sprite.Create(self, rect, pivot);
        return newSprite;
    }

3、压缩图片的功能：

public Texture2D ScaleTexture(Texture2D source, int targetWidth, int targetHeight)
    {
    
    
        Texture2D result = new Texture2D(targetWidth, targetHeight, source.format, true);
        Color[] rpixels = result.GetPixels(0);
        float incX = ((float)1 / source.width) * ((float)source.width / targetWidth);
        float incY = ((float)1 / source.height) * ((float)source.height / targetHeight);
        for (int px = 0; px < rpixels.Length; px++)
        {
    
    
            rpixels[px] = source.GetPixelBilinear(incX * ((float)px % targetWidth), incY * ((float)Mathf.Floor(px / targetWidth)));
        }
        result.SetPixels(rpixels, 0);
        result.Apply();
        return result;
    }

4、调用截屏方法即可：

private void JiepingButtonClick()
{
    
    
    ScreenShot_ReadPixelsWithCamera(Camera.main);
}