Android Open Source - GuiLib Color Picker Dialog

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License

The source code is released under:

Apache License

Java Source Code

/*
 * Copyright (C) 2007 The Android Open Source Project
 *//w  ww. j  a  v a  2s .c o  m
 * 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.gandulf.guilib.view;

import android.app.AlertDialog;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ColorMatrix;
import android.graphics.Paint;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.SweepGradient;
import android.view.MotionEvent;
import android.view.View;

import com.gandulf.guilib.R;

public class ColorPickerDialog extends AlertDialog {

  public interface OnColorChangedListener {
    void colorChanged(int color);
  }

  private OnColorChangedListener mListener;
  private int mInitialColor;

  private static class ColorPickerView extends View {
    private Paint mPaint;
    private Paint mCenterPaint;
    private final int[] mColors;
    private OnColorChangedListener mListener;
    private RectF drawRect;

    ColorPickerView(Context c, OnColorChangedListener l, int color) {
      super(c);
      mListener = l;
      mColors = new int[] { 0xFFFFFFFF, 0xFF000000, 0xFFFF0000, 0xFFFF00FF, 0xFF0000FF, 0xFF00FFFF, 0xFF00FF00,
          0xFFFFFF00, 0xFFFF0000, 0xFFFFFFFF };
      Shader s = new SweepGradient(0, 0, mColors, null);

      mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
      mPaint.setShader(s);
      mPaint.setStyle(Paint.Style.STROKE);
      mPaint.setStrokeWidth(32);

      mCenterPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
      mCenterPaint.setColor(color);
      mCenterPaint.setStrokeWidth(5);

      drawRect = new RectF();
    }

    private boolean mTrackingCenter;
    private boolean mHighlightCenter;

    @Override
    protected void onDraw(Canvas canvas) {
      float r = CENTER_X - mPaint.getStrokeWidth() * 0.5f;

      canvas.translate(CENTER_X, CENTER_X);
      drawRect.set(-r, -r, r, r);
      canvas.drawOval(drawRect, mPaint);
      canvas.drawCircle(0, 0, CENTER_RADIUS, mCenterPaint);

      if (mTrackingCenter) {
        int c = mCenterPaint.getColor();
        mCenterPaint.setStyle(Paint.Style.STROKE);

        if (mHighlightCenter) {
          mCenterPaint.setAlpha(0xFF);
        } else {
          mCenterPaint.setAlpha(0x80);
        }
        canvas.drawCircle(0, 0, CENTER_RADIUS + mCenterPaint.getStrokeWidth(), mCenterPaint);

        mCenterPaint.setStyle(Paint.Style.FILL);
        mCenterPaint.setColor(c);
      }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

      int width = MeasureSpec.getSize(widthMeasureSpec);
      int height = MeasureSpec.getSize(heightMeasureSpec);

      if (width > 0 && height > 0) {
        setMeasuredDimension(Math.min(width, height), Math.min(width, height));
      } else
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

    }

    /*
     * (non-Javadoc)
     * 
     * @see android.view.View#onSizeChanged(int, int, int, int)
     */
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
      super.onSizeChanged(w, h, oldw, oldh);

      CENTER_X = Math.min(w, h) / 2;
      CENTER_Y = Math.min(w, h) / 2;

      mPaint.setStrokeWidth((int) (CENTER_X * 0.5));
      CENTER_RADIUS = CENTER_X / 3;
    }

    private int CENTER_X = 100;
    private int CENTER_Y = 100;
    private int CENTER_RADIUS = 32;

    private int floatToByte(float x) {
      int n = java.lang.Math.round(x);
      return n;
    }

    private int pinToByte(int n) {
      if (n < 0) {
        n = 0;
      } else if (n > 255) {
        n = 255;
      }
      return n;
    }

    private int ave(int s, int d, float p) {
      return s + java.lang.Math.round(p * (d - s));
    }

    private int interpColor(int colors[], float unit) {
      if (unit <= 0) {
        return colors[0];
      }
      if (unit >= 1) {
        return colors[colors.length - 1];
      }

      float p = unit * (colors.length - 1);
      int i = (int) p;
      p -= i;

      // now p is just the fractional part [0...1) and i is the index
      int c0 = colors[i];
      int c1 = colors[i + 1];
      int a = ave(Color.alpha(c0), Color.alpha(c1), p);
      int r = ave(Color.red(c0), Color.red(c1), p);
      int g = ave(Color.green(c0), Color.green(c1), p);
      int b = ave(Color.blue(c0), Color.blue(c1), p);

      return Color.argb(a, r, g, b);
    }

    @SuppressWarnings("unused")
    private int rotateColor(int color, float rad) {
      float deg = rad * 180 / 3.1415927f;
      int r = Color.red(color);
      int g = Color.green(color);
      int b = Color.blue(color);

      ColorMatrix cm = new ColorMatrix();
      ColorMatrix tmp = new ColorMatrix();

      cm.setRGB2YUV();
      tmp.setRotate(0, deg);
      cm.postConcat(tmp);
      tmp.setYUV2RGB();
      cm.postConcat(tmp);

      final float[] a = cm.getArray();

      int ir = floatToByte(a[0] * r + a[1] * g + a[2] * b);
      int ig = floatToByte(a[5] * r + a[6] * g + a[7] * b);
      int ib = floatToByte(a[10] * r + a[11] * g + a[12] * b);

      return Color.argb(Color.alpha(color), pinToByte(ir), pinToByte(ig), pinToByte(ib));
    }

    private static final float PI = 3.1415926f;

    @Override
    public boolean onTouchEvent(MotionEvent event) {
      float x = event.getX() - CENTER_X;
      float y = event.getY() - CENTER_Y;
      boolean inCenter = java.lang.Math.sqrt(x * x + y * y) <= CENTER_RADIUS;

      switch (event.getAction()) {
      case MotionEvent.ACTION_DOWN:
        mTrackingCenter = inCenter;
        if (inCenter) {
          mHighlightCenter = true;
          invalidate();
          break;
        }
      case MotionEvent.ACTION_MOVE:
        if (mTrackingCenter) {
          if (mHighlightCenter != inCenter) {
            mHighlightCenter = inCenter;
            invalidate();
          }
        } else {
          float angle = (float) java.lang.Math.atan2(y, x);
          // need to turn angle [-PI ... PI] into unit [0....1]
          float unit = angle / (2 * PI);
          if (unit < 0) {
            unit += 1;
          }
          mCenterPaint.setColor(interpColor(mColors, unit));
          invalidate();
        }
        break;
      case MotionEvent.ACTION_UP:
        if (mTrackingCenter) {
          if (inCenter) {
            mListener.colorChanged(mCenterPaint.getColor());
          }
          mTrackingCenter = false; // so we draw w/o halo
          invalidate();
        }
        break;
      }
      return true;
    }
  }

  public ColorPickerDialog(Context context, OnColorChangedListener listener, int initialColor) {
    super(context);

    mListener = listener;
    mInitialColor = initialColor;

    OnColorChangedListener l = new OnColorChangedListener() {
      public void colorChanged(int color) {
        mListener.colorChanged(color);
        dismiss();
      }
    };
    setCanceledOnTouchOutside(true);

    setView(new ColorPickerView(getContext(), l, mInitialColor));
    setTitle(R.string.label_pick_a_color);
  }

}

Java Source Code List

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