安卓：调整大小和缩放图像的一部分 [英] Android: Resizing and scaling a part of the image

问题描述

给定一个形象，我希望能够扩展只图像的一部分。再说了，我想扩大一半的图像，这样，有一半占据了整个空间。

Given an image, I want to be able to scale only a part of that image. Say, I want to expand half of the image so that, that half takes up the whole space.

这怎么可能呢？

威尔的ImageView fitXY工作，因为我认为这会为整个原始图像才能正常工作。

Will ImageView fitXY work because I thought it'll work only for the whole original image.

@Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); LinearLayout linearLayout = new LinearLayout(this); 

           Bitmap bitmap = BitmapFactory.decodeResource(getResources(),       R.drawable.icon);   


            int width = bitmap.getWidth();   

             int height = bitmap.getHeight();   

            int newWidth = 640;   

            int newHeight = 480;   


             float scaleWidth = ((float) newWidth) / width;   

            float scaleHeight = ((float) newHeight) / height;   


            Matrix matrix = new Matrix();   

            matrix.postScale(scaleWidth, scaleHeight);   

             // create the new Bitmap object   

             Bitmap resizedBitmap = Bitmap.createBitmap(bitmap, 50, 50, width,   

                     height, matrix, true);   

             BitmapDrawable bmd = new BitmapDrawable(resizedBitmap);   



             ImageView imageView = new ImageView(this);   

             imageView.setImageDrawable(bmd);   

             imageView.setScaleType(ScaleType.CENTER);   



             linearLayout.addView(imageView, new LinearLayout.LayoutParams(   

                     LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));   

             setContentView(linearLayout);   
  } 
} 

这仅如果createBitmap，X和源第一像素的Y坐标都是0的意思，我不能把图像的一个子集。仅能够扩展整个图像。但是createBitmap意指到子集的图像。

This works only if in createBitmap, the X and Y coordinates of the first pixels in the source are 0. meaning, I'm not able to take a subset of the image. Only able to scale the whole image. But createBitmap is meant to subset an image.

在日志中，当参数不为0，我得到以下异常：java.lang.IllegalArgumentException异常：X +宽度必须＆LT; = bitmap.width（）

In the log, when the parameters are not 0, I get the following exception: java.lang.IllegalArgumentException: x + width must be <= bitmap.width()

请帮忙

推荐答案

首先，你必须创建出一种新的位图要使用缩放

First you have to create a new bitmap with the part you want to scale using

createBitmap() //pass the source bitmap, req height and width

现在从结果的位图，必须使用创建缩放位图

Now from the result bitmap, you have to create your scaled bitmap using

createScaledbitmap() //pass the result bitmap , req width, height

有关exapmle：

Bitmap originalBitmap = BitmapFactory.decodeResource(res, id);
Bitmap partImage = originalBitmap.createBitmap(width, height, config);
Bitmap scaledImage = partImage.createScaledBitmap(partImage, dstWidth, dstHeight, filter);

这篇关于安卓：调整大小和缩放图像的一部分的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！