Android example source code file (ScaleToFit.java)

This example Android source code file (ScaleToFit.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, app, center, content, end, graphicsactivity, height, height*2/3, matrix, n, os, override, paint, rectf, sampleview, scaletofit, string, ui, view, width

The ScaleToFit.java Android example source code

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.apis.graphics;

import android.app.Activity;
import android.content.Context;
import android.graphics.*;
import android.os.Bundle;
import android.view.View;

public class ScaleToFit extends GraphicsActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new SampleView(this));
    }
    
    private static class SampleView extends View {
        private final Paint   mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        private final Paint   mHairPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        private final Paint   mLabelPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        private final Matrix  mMatrix = new Matrix();
        private final RectF   mSrcR = new RectF();
        
        private static final Matrix.ScaleToFit[] sFits =
                new Matrix.ScaleToFit[] {
            Matrix.ScaleToFit.FILL,
            Matrix.ScaleToFit.START,
            Matrix.ScaleToFit.CENTER,
            Matrix.ScaleToFit.END
        };
        
        private static final String[] sFitLabels = new String[] {
            "FILL", "START", "CENTER", "END"
        };
        
        private static final int[] sSrcData = new int[] {
            80, 40, Color.RED,
            40, 80, Color.GREEN,
            30, 30, Color.BLUE,
            80, 80, Color.BLACK
        };
        private static final int N = 4;
        
        private static final int WIDTH = 52;
        private static final int HEIGHT = 52;
        private final RectF mDstR = new RectF(0, 0, WIDTH, HEIGHT);

        public SampleView(Context context) {
            super(context);

            mHairPaint.setStyle(Paint.Style.STROKE);
            mLabelPaint.setTextSize(16);
        }
        
        private void setSrcR(int index) {
            int w = sSrcData[index*3 + 0];
            int h = sSrcData[index*3 + 1];
            mSrcR.set(0, 0, w, h);
        }
        
        private void drawSrcR(Canvas canvas, int index) {
            mPaint.setColor(sSrcData[index*3 + 2]);
            canvas.drawOval(mSrcR, mPaint);
        }
        
        private void drawFit(Canvas canvas, int index, Matrix.ScaleToFit stf) {
            canvas.save();
            
            setSrcR(index);
            mMatrix.setRectToRect(mSrcR, mDstR, stf);
            canvas.concat(mMatrix);
            drawSrcR(canvas, index);
            
            canvas.restore();
            
            canvas.drawRect(mDstR, mHairPaint);
        }

        @Override protected void onDraw(Canvas canvas) {
            Paint paint = mPaint;

            canvas.drawColor(Color.WHITE);

            canvas.translate(10, 10);

            canvas.save();
            for (int i = 0; i < N; i++) {
                setSrcR(i);
                drawSrcR(canvas, i);
                canvas.translate(mSrcR.width() + 15, 0);
            }
            canvas.restore();
            
            canvas.translate(0, 100);
            for (int j = 0; j < sFits.length; j++) {
                canvas.save();
                for (int i = 0; i < N; i++) {
                    drawFit(canvas, i, sFits[j]);
                    canvas.translate(mDstR.width() + 8, 0);
                }
                canvas.drawText(sFitLabels[j], 0, HEIGHT*2/3, mLabelPaint);
                canvas.restore();
                canvas.translate(0, 80);
            }
        }
    }
}