Question

我正在制作一个自定义视图，它会给我带来意想不到的效果。我想要做的是将图片填充到视图的宽度并按比例缩放它，保持其纵横比，但它正在做一些奇怪的事情......

这是我生成的日志吐出的内容。

查看尺寸： 768x942
Pic是肖像
原稿尺寸：960x1280比例尺： 768x768
缩放位图： 768x768

现在让我解释一下日志根据代码说的内容。首先，我们让视图onMeasure本身，一旦完成，我们就可以获取视图的宽度和高度。接下来我们检查图片是横向还是纵向。然后我们只是做数学来找到我们需要缩放的大小。完成数学运算后，我们使用结果创建一个新的缩放位图。宽度是正确的，但高度应该是1024 而不是768.我无法看到它的混乱局面。

public void setBitmap(Bitmap bmp) {
this.mOriginalBitmap = bmp;

if(mHasMeasured) {
    //Make sure the view has measured itself so we can grab the width and height
Log.d("", "View size: " + String.valueOf(this.mViewWidth)
+ "x" + String.valueOf(this.mViewHeight));

int reqWidth, reqHeight; //The required sizes we need

//Get the new sizes for the pic to fit in the view and keep aspect ratio
if(this.mOriginalBitmap.getWidth() > this.mOriginalBitmap.getHeight()) {
//Landscape :/
Log.d("", "Pic is Landscape");


reqHeight = this.mViewHeight;

reqWidth = (this.mOriginalBitmap.getWidth()
             / this.mOriginalBitmap.getHeight()) * reqHeight;

} else {
//Portrait :)
Log.d("", "Pic is portrait");

reqWidth = this.mViewWidth;

reqHeight = (this.mOriginalBitmap.getHeight()
             / this.mOriginalBitmap.getWidth()) * reqWidth;

}




Log.d("", "Original Size: "
             + String.valueOf(mOriginalBitmap.getWidth()) + "x"
             + String.valueOf(mOriginalBitmap.getHeight())
             + " Scaled: " + String.valueOf(reqWidth)
             + "x" + String.valueOf(reqHeight) );

this.mBmpScaledForView = Bitmap.createScaledBitmap(mOriginalBitmap,
         reqWidth, reqHeight, false);

this.mSrc.top = 0;
this.mSrc.left = 0;
this.mSrc.right = this.mBmpScaledForView.getWidth();
this.mSrc.bottom = this.mBmpScaledForView.getHeight();
this.mDst = this.mSrc; 

Log.d("", "Scaled bitmap : "
             + String.valueOf(this.mBmpScaledForView.getWidth())
             + "x" + String.valueOf(this.mBmpScaledForView.getHeight()));

}
}

Answer 1

这里的问题是图像比率计算。 Bitmap.getHeight()和getWidth()返回整数，这是

的结果

(this.mOriginalBitmap.getHeight()
         / this.mOriginalBitmap.getWidth())

对于1的图片，

为960x1280。

这有几种选择。您可以通过转换float和getHeight()的返回值来进行getWidth()除法：

((float) this.mOriginalBitmap.getHeight()
         / (float) this.mOriginalBitmap.getWidth())

或者你可以简单地从乘法开始：

reqHeight = (reqWidth * this.mOriginalBitmap.getHeight()) / this.mOriginalBitmap.getWidth();

Answer 2

package com.riktamtech.app.utils;

import android.content.Context;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.ImageView;

/**
 * ImageView that keeps aspect ratio when scaled
 */

public class CustomImageView extends ImageView {

    public CustomImageView(Context context) {
        super(context);
    }

    public CustomImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public CustomImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        try {
            Drawable drawable = getDrawable();
            if (drawable == null) {
                setMeasuredDimension(0, 0);
            } else {
                int measuredWidth = MeasureSpec.getSize(widthMeasureSpec);
                int measuredHeight = MeasureSpec.getSize(heightMeasureSpec);
                if (measuredHeight == 0 && measuredWidth == 0) { // Height and
                                                                    // width set
                                                                    // to
                                                                    // wrap_content
                    setMeasuredDimension(measuredWidth, measuredHeight);
                } else if (measuredHeight == 0) { // Height set to wrap_content
                    int width = measuredWidth;
                    int height = width * drawable.getIntrinsicHeight()
                            / drawable.getIntrinsicWidth();
                    setMeasuredDimension(width, height);
                } else if (measuredWidth == 0) { // Width set to wrap_content
                    int height = measuredHeight;
                    int width = height * drawable.getIntrinsicWidth()
                            / drawable.getIntrinsicHeight();
                    setMeasuredDimension(width, height);
                } else { // Width and height are explicitly set (either to
                            // match_parent or to exact value)
                    setMeasuredDimension(measuredWidth, measuredHeight);
                }
            }
        } catch (Exception e) {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        }
    }

}

将图像缩放为自定义视图的宽度

2 个答案: