如何将大图像的部分裁剪到 ImageView

Posted 2023-02-25

【中文标题】如何将大图像的部分裁剪到 ImageView

【英文标题】：How do I crop portions of large image to an ImageView

【发布时间】：2016-06-19 15:55:48

【问题描述】：

假设我有一张看起来像左边的图片... 每个标志是 30x20px。

如何显示区域 0,60 到 30,80？我也希望以后能够如此高档。

【参考方案1】：

您可以使用此方法从您的偏移量创建另一个位图

/**
 * Returns an immutable bitmap from the specified subset of the source
 * bitmap. The new bitmap may be the same object as source, or a copy may
 * have been made. It is initialized with the same density as the original
 * bitmap.
 *
 * @param source   The bitmap we are subsetting
 * @param x        The x coordinate of the first pixel in source
 * @param y        The y coordinate of the first pixel in source
 * @param width    The number of pixels in each row
 * @param height   The number of rows
 * @return A copy of a subset of the source bitmap or the source bitmap itself.
 * @throws IllegalArgumentException if the x, y, width, height values are
 *         outside of the dimensions of the source bitmap, or width is <= 0,
 *         or height is <= 0
 */
public static Bitmap createBitmap(Bitmap source, int x, int y, int width, int height) 
    return createBitmap(source, x, y, width, height, null, false);

另一个选项是创建一个自定义 ImageView，然后覆盖 onDraw() 方法以从您的偏移量在 Canvas 上绘制位图

使用Canvas类的这个方法

public void drawBitmap(@NonNull Bitmap bitmap, float left, float top, @Nullable Paint paint)