在自定义ImageView中顶部对齐图像

Question

I am using ViewPager from TouchImageView to load images to my app. This is the TouchImageView.java which responsible for the loading of image.

float redundantXSpace = viewWidth - (scaleX * drawableWidth);
        float redundantYSpace = viewHeight - (scaleY * drawableHeight);
        matchViewWidth = viewWidth - redundantXSpace;
        matchViewHeight = viewHeight - redundantYSpace;
        if (!isZoomed() && !imageRenderedAtLeastOnce) {
            //
            // Stretch and center image to fit view
            //
            matrix.setScale(scaleX, scaleY);
            matrix.postTranslate(redundantXSpace / 2, redundantYSpace / 2);
            normalizedScale = 1;

        } else {
            //
            // These values should never be 0 or we will set viewWidth and viewHeight
            // to NaN in translateMatrixAfterRotate. To avoid this, call savePreviousImageValues
            // to set them equal to the current values.
            //
            if (prevMatchViewWidth == 0 || prevMatchViewHeight == 0) {
                savePreviousImageValues();
            }

            prevMatrix.getValues(m);

The code load my images on vertical center. What I want to achieve is to load the images on vertical top. If I change the matchViewHeight = viewHeight - redundantYSpace; to matchViewHeight = viewHeight; , the image will fill the entire height. What modification should I made to make to align on vertical top?

Answer 1

use

matrix.setScale(scaleX, scaleY);
matrix.postTranslate(redundantXSpace / 2, 0);

postTranslate - moved the image. You do not need to move along the y axis for align on top.

For align on bottom:

matrix.setScale(scaleX, scaleY);
matrix.postTranslate(redundantXSpace / 2, redundantYSpace );