Android：用白色填充位图

Question

如何将位图左侧的 10 行全部设置为白色？ 我有一个必须在左侧填充的位图。我想我可以在旧的 getpixel 上为每个位置创建一个新的图像，并在新的一个（白色或彩色）上设置像素而不是返回新的位图......这是错的吗？ 有什么建议吗？非常感谢！

Answer 1

我这样做只是为了从各个方面进行填充。希望它会帮助某人。 https://stackoverflow.com/a/44060669/6480433 & https://stackoverflow.com/a/6957333/6480433 这些答案的组合。

Bitmap outputimage = Bitmap.createBitmap(Src.getWidth() + padding_x,Src.getHeight() + padding_y, Bitmap.Config.ARGB_8888);
        Canvas can = new Canvas(outputimage);
        can.drawBitmap(Src, padding_x, padding_y, null);

        Bitmap output = Bitmap.createBitmap(outputimage.getWidth()+padding_x, outputimage.getHeight() + padding_y, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(output);
        canvas.drawBitmap(outputimage, 0, 0, null);    
  return output;

Answer 2

这是一个使用 RxJava 的 kotlin 扩展函数来完成它。我还没有完全测试，但基于结合以前的答案得到一些东西

fun Bitmap.pad(top: Float = 0F, bottom: Float = 0F, left: Float = 0F, right: Float = 0F): Single<Bitmap> {
    return Single.create<Bitmap> { emitter ->
        val output = Bitmap.createBitmap(
            (width + left + right).toInt(),
            (height + top + bottom).toInt(),
            Bitmap.Config.ARGB_8888
        )
        val canvas = Canvas(output)

        canvas.drawBitmap(this, left, top, null)

        emitter.onSuccess(output)
    }.subscribeOn(Schedulers.computation())
}

我认为协程版本只是

suspend fun Bitmap.pad(top: Float = 0F, bottom: Float = 0F, left: Float = 0F, right: Float = 0F): Bitmap {
    val output = Bitmap.createBitmap(
        (width + left + right).toInt(),
        (height + top + bottom).toInt(),
        Bitmap.Config.ARGB_8888
    )
    val canvas = Canvas(output)

    canvas.drawBitmap(this, left, top, null)

    return output
}

Answer 3

public Bitmap addPaddingTopForBitmap(Bitmap bitmap, int paddingTop) {
    Bitmap outputBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight() + paddingTop, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(outputBitmap);
    canvas.drawColor(Color.RED);
    canvas.drawBitmap(bitmap, 0, paddingTop, null);
    return outputBitmap;
}

public Bitmap addPaddingBottomForBitmap(Bitmap bitmap, int paddingBottom) {
    Bitmap outputBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight() + paddingBottom, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(outputBitmap);
    canvas.drawColor(Color.RED);
    canvas.drawBitmap(bitmap, 0, 0, null);
    return outputBitmap;
}


public Bitmap addPaddingRightForBitmap(Bitmap bitmap, int paddingRight) {
    Bitmap outputBitmap = Bitmap.createBitmap(bitmap.getWidth() + paddingRight, bitmap.getHeight(), Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(outputBitmap);
    canvas.drawColor(Color.RED);
    canvas.drawBitmap(bitmap, 0, 0, null);
    return outputBitmap;
}

public Bitmap addPaddingLeftForBitmap(Bitmap bitmap, int paddingLeft) {
    Bitmap outputBitmap = Bitmap.createBitmap(bitmap.getWidth() + paddingLeft, bitmap.getHeight(), Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(outputBitmap);
    canvas.drawColor(Color.RED);
    canvas.drawBitmap(bitmap, paddingLeft, 0, null);
    return outputBitmap;
}

Answer 4

您可以改为创建具有额外填充像素数的新位图。 将此设置为画布位图并使用所需颜色为整个图像着色，然后复制您的位图。

public Bitmap pad(Bitmap Src, int padding_x, int padding_y) {
    Bitmap outputimage = Bitmap.createBitmap(Src.getWidth() + padding_x,Src.getHeight() + padding_y, Bitmap.Config.ARGB_8888);
    Canvas can = new Canvas(outputimage);
    can.drawARGB(FF,FF,FF,FF); //This represents White color
    can.drawBitmap(Src, padding_x, padding_y, null);
    return outputimage;
}

Answer 5

你可能想看看这里：

http://download.oracle.com/javase/1.4.2/docs/api/java/awt/image/BufferedImage.html

您可能想要使用的方法是：getHeight() 然后您知道要设置多少像素并在 10 列上进行迭代

和setRGB(int x, int y, int RGB)设置像素