How set imageview scaletype to topCrop

Question

I'm coding android and I have a imageview. I want to set scaletype of this to topcrop. I could find centercrop in options, but it's not my request. How do I do?

score 32 · Accepted Answer · answered Apr 21 '15 at 21:30

Custom Android ImageView for top-crop scaling of the contained drawable.

import android.content.Context;
import android.graphics.Matrix;
import android.widget.ImageView;

/**
* ImageView to display top-crop scale of an image view.
*
* @author Chris Arriola
*/
public class TopCropImageView extends ImageView {

public TopCropImageView(Context context) {
    super(context);
    setScaleType(ScaleType.MATRIX);
}

@Override
protected boolean setFrame(int l, int t, int r, int b) {
    final Matrix matrix = getImageMatrix();

    float scale;
    final int viewWidth = getWidth() - getPaddingLeft() - getPaddingRight();
    final int viewHeight = getHeight() - getPaddingTop() - getPaddingBottom();
    final int drawableWidth = getDrawable().getIntrinsicWidth();
    final int drawableHeight = getDrawable().getIntrinsicHeight();

    if (drawableWidth * viewHeight > drawableHeight * viewWidth) {
        scale = (float) viewHeight / (float) drawableHeight;
    } else {
        scale = (float) viewWidth / (float) drawableWidth;
    }

    matrix.setScale(scale, scale);
    setImageMatrix(matrix);

    return super.setFrame(l, t, r, b);
}        
}

https://gist.github.com/arriolac/3843346

how to implement this. i asked a question regarding this http://stackoverflow.com/questions/32359213/trying-to-use-custom-imageview-topcrop-in-android-but-the-the-app-stops. — Santhosh, Sep 02 '15 at 17:33
@Jay it works great. Im making matrix computations in onLayout() method, which gets called in on rotation also, where setFrame doesn't. — box, Jul 29 '16 at 12:00
I call super.setFrame(l, t, r, b); in the beginning or getWidth() will return 0 — JackWu, Mar 07 '18 at 14:06

score 14 · Answer 2 · answered Jun 08 '17 at 20:41

14

I just wanted a temporary solution without excess work . Try this

<ImageView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:scaleType="centerCrop"
    android:scrollY="-100dp"
    android:id="@+id/poster"
   />

scrollY pulls your image up or down. Try it with different dp's and you 'll find the right size.

answered Jun 08 '17 at 20:41

rahulxyz

437
4
12

8

While this achieves the task at hand, it does not work for different screen resolutions or parent view sizes. Probably not recommended for production, as you will get unexpected results in the wild. :) – DoctorD Jun 10 '17 at 17:14
Yes, that's true i learned it the hard way. It behaves differently on various screens. – rahulxyz Jun 10 '17 at 19:03
I only needed to move the image slightly and this worked perfectly, thanks. – HB. Jul 06 '18 at 08:28

score 4 · Answer 3 · edited May 23 '17 at 12:17

4

I don't believe you need a custom Image View for this. All you have to do is set the scaleType to matrix and set a custom matrix to the ImageView.

Refer: https://stackoverflow.com/a/38049348/4747587

edited May 23 '17 at 12:17

Community

1
1

answered Jun 27 '16 at 08:42

Henry

17,490
7
63
98

score 1 · Answer 4 · answered Feb 23 '21 at 22:06

Fixed version:

setFrame calling asap
not reusing Matrix -> it caused issue that when image realoaded too soon (with Picasso), the image was scaled too much

import android.content.Context
import android.graphics.Matrix
import android.util.AttributeSet
import androidx.appcompat.widget.AppCompatImageView

class TopCropImageView @JvmOverloads constructor(
    context: Context,
    attrs: AttributeSet? = null,
    defStyleAttr: Int = 0,
) : AppCompatImageView(context, attrs, defStyleAttr) {

    init {
        scaleType = ScaleType.MATRIX
    }

    override fun setFrame(l: Int, t: Int, r: Int, b: Int): Boolean {
        super.setFrame(l, t, r, b)
        val matrix = Matrix()
        val scale: Float
        val viewWidth: Int = width - paddingLeft - paddingRight
        val viewHeight: Int = height - paddingTop - paddingBottom
        val drawableWidth: Int = drawable.intrinsicWidth
        val drawableHeight: Int = drawable.intrinsicHeight
        scale = if (drawableWidth * viewHeight > drawableHeight * viewWidth) {
            viewHeight.toFloat() / drawableHeight.toFloat()
        } else {
            viewWidth.toFloat() / drawableWidth.toFloat()
        }
        matrix.setScale(scale, scale)
        imageMatrix = matrix
        return true
    }
}

How set imageview scaletype to topCrop

4 Answers4

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