Java如何设置jpg质量

Question

只是想编辑一些代码，以使输出jpg质量不是默认的低质量设置，

try
        {
            ImageIO.write(var6, "jpg", var7);
        }

.....当前正在使用。

我看过其他一些设置质量的Java示例，但对Java不太熟悉，我在理解如何插入东西和重做一些示例方面遇到了麻烦，这些示例在使用Java设置图像质量方面已经见过。

ImageWriteParam iwparam = new JPEGImageWriteParam(Locale.getDefault());
    iwparam.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
    iwparam.setCompressionQuality(quality);
    writer.write(null, new IIOImage(image, null, null), iwparam);

这是我要开始工作的代码........

public static String func_74292_a(File par0File, String par1Str, int par2, int par3)
{
    File var4 = new File(par0File, "screenshots");
    var4.mkdir();
    int var5 = par2 * par3;

    if (field_74293_b == null || field_74293_b.capacity() < var5)
    {
        field_74293_b = BufferUtils.createIntBuffer(var5);
        field_74294_c = new int[var5];
    }

    GL11.glPixelStorei(GL11.GL_PACK_ALIGNMENT, 1);
    GL11.glPixelStorei(GL11.GL_UNPACK_ALIGNMENT, 1);
    field_74293_b.clear();
    GL11.glReadPixels(0, 0, par2, par3, GL12.GL_BGRA, GL12.GL_UNSIGNED_INT_8_8_8_8_REV, field_74293_b);
    field_74293_b.get(field_74294_c);
    func_74289_a(field_74294_c, par2, par3);
    BufferedImage var6 = new BufferedImage(par2, par3, 1);
    var6.setRGB(0, 0, par2, par3, field_74294_c, 0, par2);

    if (par1Str == null)
    {
        var7 = func_74290_a(var4);
    }
    else
    {
        var7 = new File(var4, par1Str);
    }

    try
    {
        ImageIO.write(var6, "jpg", var7);
    }
    catch (IOException var8)
    {
        ;
    }

    Thread var7x = new Thread(new ScreenShotHelper$1());
    var7x.start();
    return "\u00a7aUploading Screenshot....";
}

private static File func_74290_a(File par0File)
{
    String var1 = dateFormat.format(new Date()).toString();
    int var2 = 1;

    while (true)
    {
        File var3 = new File(par0File, var1 + (var2 == 1 ? "" : "_" + var2) + ".jpg");

        if (!var3.exists())
        {
            return var3;
        }

        ++var2;
    }
}

Answer 1

终于用这段代码做到了…

try
{

    ImageOutputStream  ios =  ImageIO.createImageOutputStream(var7);
    Iterator<ImageWriter> iter = ImageIO.getImageWritersByFormatName("jpeg");
    ImageWriter writer = iter.next();
    ImageWriteParam iwp = writer.getDefaultWriteParam();
    iwp.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
    iwp.setCompressionQuality(0.85f);
    writer.setOutput(ios);
    writer.write(null, new IIOImage(var6,null,null),iwp);
    writer.dispose();

    //ImageIO.write(var6, "jpg", var7);
}