安卓画布绘制文本从宽度设置字体大小？

android java android-canvas

2022-08-31 15:32:11

我想使用一定宽度的文字canvas.drawtext

例如，无论输入文本是什么，文本的宽度都应始终为。400px

如果输入文本较长，它将减小字体大小，如果输入文本较短，它将相应地增加字体大小。

答案 1

这是一种更有效的方法：

/**
 * Sets the text size for a Paint object so a given string of text will be a
 * given width.
 * 
 * @param paint
 *            the Paint to set the text size for
 * @param desiredWidth
 *            the desired width
 * @param text
 *            the text that should be that width
 */
private static void setTextSizeForWidth(Paint paint, float desiredWidth,
        String text) {

    // Pick a reasonably large value for the test. Larger values produce
    // more accurate results, but may cause problems with hardware
    // acceleration. But there are workarounds for that, too; refer to
    // http://stackoverflow.com/questions/6253528/font-size-too-large-to-fit-in-cache
    final float testTextSize = 48f;

    // Get the bounds of the text, using our testTextSize.
    paint.setTextSize(testTextSize);
    Rect bounds = new Rect();
    paint.getTextBounds(text, 0, text.length(), bounds);

    // Calculate the desired size as a proportion of our testTextSize.
    float desiredTextSize = testTextSize * desiredWidth / bounds.width();

    // Set the paint for that size.
    paint.setTextSize(desiredTextSize);
}

然后，您需要做的就是（400是问题中的示例宽度）。setTextSizeForWidth(paint, 400, str);

为了获得更高的效率，您可以将静态类成员，以免每次都对其进行实例化。但是，这可能会引入并发问题，并且可能会妨碍代码的清晰度。Rect

答案 2

试试这个：

/**
 * Retrieve the maximum text size to fit in a given width.
 * @param str (String): Text to check for size.
 * @param maxWidth (float): Maximum allowed width.
 * @return (int): The desired text size.
 */
private int determineMaxTextSize(String str, float maxWidth)
{
    int size = 0;       
    Paint paint = new Paint();

    do {
        paint.setTextSize(++ size);
    } while(paint.measureText(str) < maxWidth);

    return size;
} //End getMaxTextSize()