Android - 在自定义视图中滚动位图

发布于 2024-11-06 01:44:11 字数 533 浏览 0 评论 0原文

我有一个尺寸为 400 x 70 像素的位图。我想将此位图向上滚动一行并用新像素填充第 70 行。我尝试通过将位图复制到 IntBuffer 来滚动位图，将其复制到另一个 IntBuffer （从第二行开始），然后将其写回位图。这可行，但需要大量的 CPU 能力，而且速度有点慢。有没有更快的方法来做到这一点？

private Bitmap shift(Bitmap bitmap)
{
    buffer.rewind();
    buffer1.rewind();
    bitmap.copyPixelsToBuffer(buffer);
    buffer.position(bitmap.getWidth());
    buffer1.put(buffer.array(), bitmap.getWidth()*2, bitmap.getWidth() * bitmap.getHeight());
    buffer1.rewind();
    bitmap.copyPixelsFromBuffer(buffer1);

    return bitmap;
}

原文

I have a bitmap with the size of 400 x 70 pixels. I would like to scroll this bitmap up by one row and fill up row 70 with new pixels.
I have tried to scroll the bitmap by copying it to an IntBuffer , copy it to another IntBuffer (starting at the second row) and the then write it back to the bitmap.
This works but it takes a lot of CPU power and it is kind of slow.
Is there any faster way to do this?

private Bitmap shift(Bitmap bitmap)
{
    buffer.rewind();
    buffer1.rewind();
    bitmap.copyPixelsToBuffer(buffer);
    buffer.position(bitmap.getWidth());
    buffer1.put(buffer.array(), bitmap.getWidth()*2, bitmap.getWidth() * bitmap.getHeight());
    buffer1.rewind();
    bitmap.copyPixelsFromBuffer(buffer1);

    return bitmap;
}

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瀟灑尐姊 2024-11-13 01:44:11

这是使用画布实现此目的的一种方法：

    canvas.drawBitmap(bgr, bgrPosition, 0, null); 
    canvas.drawBitmap(bgr, 0 - bgrW + bgrPosition, 0, null);

    //next value for the background's position 
    if ( (bgrPosition += bgrDx) > bgrW){
        bgrPosition = 0;
    }

bgrDx 是滚动速度（尝试 bgrDx = 1），而 bgrW 是 bgr 位图的宽度。
此方法重复图像并产生无限滚动，但是您需要使用循环图像（两端相同）以使滚动看起来无缝。也许您应该尝试一下，看看它是否对您有更好的效果。

This is one way to do it using canvas:

    canvas.drawBitmap(bgr, bgrPosition, 0, null); 
    canvas.drawBitmap(bgr, 0 - bgrW + bgrPosition, 0, null);

    //next value for the background's position 
    if ( (bgrPosition += bgrDx) > bgrW){
        bgrPosition = 0;
    }

bgrDx is the speed of scrolling try bgrDx = 1, while bgrW is the width of the bgr bitmap.
This method repeats the image and produces an infinite scroll, however you would need to use a looped image (the same on both ends) to make the scroll look seamless. Perhaps you should experiment with this and see if it performs any better for you.

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