将Unity UGUI中RawImage组件身上的Texture转换为我们想要的字节数组 指定格式

//如果你想复制一张图片 就把注释打开 更改返回值就可以了
    private byte[] duplicateTexture(Texture2D source)
    {
        RenderTexture renderTex = RenderTexture.GetTemporary(
                    source.width,
                    source.height,
                    0,
                    RenderTextureFormat.Default,
                    RenderTextureReadWrite.Linear);

        Graphics.Blit(source, renderTex);
        RenderTexture previous = RenderTexture.active;
        RenderTexture.active = renderTex;
        Texture2D readableText = new Texture2D(source.width, source.height);
        readableText.ReadPixels(new Rect(0, 0, renderTex.width, renderTex.height), 0, 0);
        readableText.Apply();
        //这里可以转 JPG PNG EXR  Unity都封装了固定的Api
        byte[] bytes = readableText.EncodeToPNG();
        return bytes;
        //RenderTexture.active = previous;
        //RenderTexture.ReleaseTemporary(renderTex);
        //return readableText;
    }