Scale To Fit : Canvas « 2D Graphics « Android






Scale To Fit

    
/*
 * Copyright (C) 2007 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 app.test;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Picture;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewParent;

public class Test 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) {
      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);
      }
    }
  }
}

class GraphicsActivity extends Activity {
  // set to true to test Picture
  private static final boolean TEST_PICTURE = false;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
  }

  @Override
  public void setContentView(View view) {
    if (TEST_PICTURE) {
      ViewGroup vg = new PictureLayout(this);
      vg.addView(view);
      view = vg;
    }

    super.setContentView(view);
  }
}

class PictureLayout extends ViewGroup {
  private final Picture mPicture = new Picture();

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

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

  @Override
  public void addView(View child) {
    if (getChildCount() > 1) {
      throw new IllegalStateException(
          "PictureLayout can host only one direct child");
    }

    super.addView(child);
  }

  @Override
  public void addView(View child, int index) {
    if (getChildCount() > 1) {
      throw new IllegalStateException(
          "PictureLayout can host only one direct child");
    }

    super.addView(child, index);
  }

  @Override
  public void addView(View child, LayoutParams params) {
    if (getChildCount() > 1) {
      throw new IllegalStateException(
          "PictureLayout can host only one direct child");
    }

    super.addView(child, params);
  }

  @Override
  public void addView(View child, int index, LayoutParams params) {
    if (getChildCount() > 1) {
      throw new IllegalStateException(
          "PictureLayout can host only one direct child");
    }

    super.addView(child, index, params);
  }

  @Override
  protected LayoutParams generateDefaultLayoutParams() {
    return new LayoutParams(LayoutParams.MATCH_PARENT,
        LayoutParams.MATCH_PARENT);
  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    final int count = getChildCount();

    int maxHeight = 0;
    int maxWidth = 0;

    for (int i = 0; i < count; i++) {
      final View child = getChildAt(i);
      if (child.getVisibility() != GONE) {
        measureChild(child, widthMeasureSpec, heightMeasureSpec);
      }
    }

    maxWidth += getPaddingLeft() + getPaddingRight();
    maxHeight += getPaddingTop() + getPaddingBottom();

    Drawable drawable = getBackground();
    if (drawable != null) {
      maxHeight = Math.max(maxHeight, drawable.getMinimumHeight());
      maxWidth = Math.max(maxWidth, drawable.getMinimumWidth());
    }

    setMeasuredDimension(resolveSize(maxWidth, widthMeasureSpec),
        resolveSize(maxHeight, heightMeasureSpec));
  }

  private void drawPict(Canvas canvas, int x, int y, int w, int h, float sx,
      float sy) {
    canvas.save();
    canvas.translate(x, y);
    canvas.clipRect(0, 0, w, h);
    canvas.scale(0.5f, 0.5f);
    canvas.scale(sx, sy, w, h);
    canvas.drawPicture(mPicture);
    canvas.restore();
  }

  @Override
  protected void dispatchDraw(Canvas canvas) {
    super.dispatchDraw(mPicture.beginRecording(getWidth(), getHeight()));
    mPicture.endRecording();

    int x = getWidth() / 2;
    int y = getHeight() / 2;

    if (false) {
      canvas.drawPicture(mPicture);
    } else {
      drawPict(canvas, 0, 0, x, y, 1, 1);
      drawPict(canvas, x, 0, x, y, -1, 1);
      drawPict(canvas, 0, y, x, y, 1, -1);
      drawPict(canvas, x, y, x, y, -1, -1);
    }
  }

  @Override
  public ViewParent invalidateChildInParent(int[] location, Rect dirty) {
    location[0] = getLeft();
    location[1] = getTop();
    dirty.set(0, 0, getWidth(), getHeight());
    return getParent();
  }

  @Override
  protected void onLayout(boolean changed, int l, int t, int r, int b) {
    final int count = super.getChildCount();

    for (int i = 0; i < count; i++) {
      final View child = getChildAt(i);
      if (child.getVisibility() != GONE) {
        final int childLeft = getPaddingLeft();
        final int childTop = getPaddingTop();
        child.layout(childLeft, childTop,
            childLeft + child.getMeasuredWidth(),
            childTop + child.getMeasuredHeight());

      }
    }
  }
}

   
    
    
    
  








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