Android uses Glide to load network pictures and scale them equally

When loading android pictures, due to the limited screen of mobile phones, when many large pictures are loaded, we require equal scaling, such as scaling the height according to a fixed width, so that the size ratio of the pictures can be scaled accordingly, but the pictures are not deformed. Obviously, it can't be implemented according to android: scaleType, because there will be many limitations, so you must write your own algorithm.

Scaling through Glide

In fact, glide provides such a method. Specifically, it shows the setResource method that inherits Transformation.

(1) Get the width and height of network or local pictures first
(2) Obtain the desired target width
(3) Obtain the height of the target in proportion
(4) Create a new map according to the width and height of the target

/**
 * ===========================================
 *  Version    Ben: 1.0
 *  Describe    Description: Set the equal scale of the picture 
 * <p>glide Processing pictures .</p>
 * ===========================================
 */
public class TransformationUtils extends ImageViewTarget<Bitmap> {
  private ImageView target;
  public TransformationUtils(ImageView target) {
    super(target);
    this.target = target;
  }
  @Override
  protected void setResource(Bitmap resource) {
    view.setImageBitmap(resource);
    // Get the width and height of the original image 
    int width = resource.getWidth();
    int height = resource.getHeight();
    // Get imageView Width of 
    int imageViewWidth = target.getWidth();
    // Calculate the scaling ratio 
    float sy = (float) (imageViewWidth * 0.1) / (float) (width * 0.1);
    // Calculate the height of the picture after equal scale enlargement 
    int imageViewHeight = (int) (height * sy);
    ViewGroup.LayoutParams params = target.getLayoutParams();
    params.height = imageViewHeight;
    target.setLayoutParams(params);
  }
}

Then set transform in Glide

Glide.with(this)
          .load(newActiviteLeftBannerUrl)
          .asBitmap()
          .placeholder(R.drawable.placeholder)
          .into(new TransformationUtils(target));

Transformation This is a very powerful feature of Glide, which allows you to image in load- > In the middle of into ImageView, this pair of pictures is transformed in series 1. For example, if you want to do Gaussian blur, add rounded corners, do gray processing, round pictures, etc., you can do it through Transformation.

Summarize