Unity 压缩texture

时间：2022-01-08 16:35:29

当我们往服务器保存图片时

并不会仅仅保留原图

一般会另外保存一张缩略图

当加载文件夹时只加载缩略图

当在点击缩略图打开图片时

再加载原缩略图

以节省时间和内存

下面以将屏幕截图保存到服务器为例

将屏幕截图和截图缩略图保存到服务器

    private IEnumerator UploadPNG(string id)

    {

        yield return new WaitForEndOfFrame();

        int width = Screen.width;

        int height = Screen.height;

        //屏幕截图

        Texture2D tex = new Texture2D(width, height, TextureFormat.ARGB32, false);

        tex.ReadPixels(new Rect(0, 0, width, height), 0, 0);

        tex.Apply();

        byte[] bytes = tex.EncodeToPNG();

        //缩略图(256*256)

        Texture2D texThumb = new Texture2D(256, 256);

        //压缩图片

        Color[] destPix = new Color[texThumb.width * texThumb.height];

        float warpFactor = 1.0f;

        int y = 0;

        while (y < texThumb.height)

        {

            int x = 0;

            while (x < texThumb.width)

            {

                float xFrac = x * 1.0F / (texThumb.width - 1);

                float yFrac = y * 1.0F / (texThumb.height - 1);

                float warpXFrac = Mathf.Pow(xFrac, warpFactor);

                float warpYFrac = Mathf.Pow(yFrac, warpFactor);

                Color c0 = tex.GetPixelBilinear(warpXFrac, warpYFrac);

                xFrac = (x - 1) * 1.0F / (texThumb.width - 1);

                yFrac = y * 1.0F / (texThumb.height - 1);

                warpXFrac = Mathf.Pow(xFrac, warpFactor);

                warpYFrac = Mathf.Pow(yFrac, warpFactor);

                Color c1 = tex.GetPixelBilinear(warpXFrac, warpYFrac);

                xFrac = (x + 1) * 1.0F / (texThumb.width - 1);

                yFrac = y * 1.0F / (texThumb.height - 1);

                warpXFrac = Mathf.Pow(xFrac, warpFactor);

                warpYFrac = Mathf.Pow(yFrac, warpFactor);

                Color c2 = tex.GetPixelBilinear(warpXFrac, warpYFrac);

                xFrac = (x + 1) * 1.0F / (texThumb.width - 1);

                yFrac = (y - 1) * 1.0F / (texThumb.height - 1);

                warpXFrac = Mathf.Pow(xFrac, warpFactor);

                warpYFrac = Mathf.Pow(yFrac, warpFactor);

                Color c3 = tex.GetPixelBilinear(warpXFrac, warpYFrac);

                xFrac = (x - 0) * 1.0F / (texThumb.width - 1);

                yFrac = (y - 1) * 1.0F / (texThumb.height - 1);

                warpXFrac = Mathf.Pow(xFrac, warpFactor);

                warpYFrac = Mathf.Pow(yFrac, warpFactor);

                Color c4 = tex.GetPixelBilinear(warpXFrac, warpYFrac);

                xFrac = (x - 1) * 1.0F / (texThumb.width - 1);

                yFrac = (y - 1) * 1.0F / (texThumb.height - 1);

                warpXFrac = Mathf.Pow(xFrac, warpFactor);

                warpYFrac = Mathf.Pow(yFrac, warpFactor);

                Color c5 = tex.GetPixelBilinear(warpXFrac, warpYFrac);

                xFrac = (x + 1) * 1.0F / (texThumb.width - 1);

                yFrac = (y + 1) * 1.0F / (texThumb.height - 1);

                warpXFrac = Mathf.Pow(xFrac, warpFactor);

                warpYFrac = Mathf.Pow(yFrac, warpFactor);

                Color c6 = tex.GetPixelBilinear(warpXFrac, warpYFrac);

                xFrac = (x - 0) * 1.0F / (texThumb.width - 1);

                yFrac = (y + 1) * 1.0F / (texThumb.height - 1);

                warpXFrac = Mathf.Pow(xFrac, warpFactor);

                warpYFrac = Mathf.Pow(yFrac, warpFactor);

                Color c7 = tex.GetPixelBilinear(warpXFrac, warpYFrac);

                xFrac = (x - 1) * 1.0F / (texThumb.width - 1);

                yFrac = (y + 1) * 1.0F / (texThumb.height - 1);

                warpXFrac = Mathf.Pow(xFrac, warpFactor);

                warpYFrac = Mathf.Pow(yFrac, warpFactor);

                Color c8 = tex.GetPixelBilinear(warpXFrac, warpYFrac);

                Color cr = c0 * 0.25f + c1 * 0.125f + c2 * 0.125f + c3 * 0.0625f + c4 * 0.125f + c5 * 0.0625f + c6 * 0.0625f + c7 * 0.125f + c8 * 0.0625f;

                destPix[y * texThumb.width + x] = cr;

                x++;

            }

            y++;

        }

        texThumb.SetPixels(destPix);

        texThumb.Apply();

        byte[] bytesThumb = texThumb.EncodeToPNG();

        Destroy(tex);

        Destroy(texThumb);

        //WWWForm上传到服务器

        WWWForm form = new WWWForm();

        form.AddField("cmd", "savedraw");

        form.AddBinaryData("screenshot", bytesThumb);

        form.AddBinaryData("draw", bytes);

        WWW w = new WWW(url, form);

        yield return w;

        if (w.error != null)

        {

            Debug.Log("Error:" + w.error);

        }

        else

            Debug.Log("OK");

    }

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