Mega Code Archive
Brightness Slider
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/*
* Copyright (C) 2008 OpenIntents.org
*
* 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 org.openintents.widget;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.LinearGradient;
import android.graphics.Paint;
import android.graphics.Shader;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
/**
* BrightnessSlider.
*
* @author Peli, based on API demo code.
*
*/
public class ColorSlider extends View {
/** Default widget width */
public int defaultWidth;
/** Default widget height */
public int defaultHeight;
private Paint mPaint;
private int mColor1;
private int mColor2;
private OnColorChangedListener mListener;
/**
* Constructor. This version is only needed for instantiating the object
* manually (not from a layout XML file).
*
* @param context
*/
public ColorSlider(Context context) {
super(context);
init();
}
/**
* Construct object, initializing with any attributes we understand from a
* layout file.
*
* These attributes are defined in res/values/attrs.xml .
*
* @see android.view.View#View(android.content.Context,
* android.util.AttributeSet, java.util.Map)
*/
public ColorSlider(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO what happens with inflateParams
init();
}
/**
* Initializes variables.
*/
void init() {
mColor1 = 0xFFFFFFFF;
mColor2 = 0xFF000000;
mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mPaint.setStyle(Paint.Style.FILL);
}
@Override
protected void onDraw(Canvas canvas) {
Shader s = new LinearGradient(0, 0, 0, getHeight(), mColor1, mColor2, Shader.TileMode.CLAMP);
mPaint.setShader(s);
canvas.drawRect(0, 0, getWidth(), getHeight(), mPaint);
}
/**
* @see android.view.View#measure(int, int)
*/
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
setMeasuredDimension(measureWidth(widthMeasureSpec),
measureHeight(heightMeasureSpec));
}
/**
* Determines the width of this view
*
* @param measureSpec
* A measureSpec packed into an int
* @return The width of the view, honoring constraints from measureSpec
*/
private int measureWidth(int measureSpec) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if (specMode == MeasureSpec.EXACTLY) {
// We were told how big to be
result = specSize;
} else {
// Default width:
result = defaultWidth;
if (specMode == MeasureSpec.AT_MOST) {
// Respect AT_MOST value if that was what is called for by
// measureSpec
result = Math.min(result, specSize);
}
}
return result;
}
/**
* Determines the height of this view
*
* @param measureSpec
* A measureSpec packed into an int
* @return The height of the view, honoring constraints from measureSpec
*/
private int measureHeight(int measureSpec) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if (specMode == MeasureSpec.EXACTLY) {
// We were told how big to be
result = specSize;
} else {
// Default height
result = defaultHeight;
if (specMode == MeasureSpec.AT_MOST) {
// Respect AT_MOST value if that was what is called for by
// measureSpec
result = Math.min(result, specSize);
}
}
return result;
}
public void setColors(int color1, int color2) {
mColor1 = color1;
mColor2 = color2;
invalidate();
}
public void setOnColorChangedListener(
OnColorChangedListener colorListener) {
mListener = colorListener;
}
private int ave(int s, int d, float p) {
return s + java.lang.Math.round(p * (d - s));
}
private int interpColor(int color1, int color2, float unit) {
if (unit <= 0) {
return color1;
}
if (unit >= 1) {
return color2;
}
float p = unit;
// now p is just the fractional part [0...1) and i is the index
int c0 = color1;
int c1 = color2;
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);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
float x = event.getX();
float y = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_MOVE:
float unit = (float) y / ((float) getHeight());
int newcolor = interpColor(mColor1, mColor2, unit);
if (mListener != null) {
mListener.onColorChanged(this, newcolor);
}
invalidate();
break;
case MotionEvent.ACTION_UP:
break;
}
return true;
}
}
/**
* Interface for notifications of position change of slider.
*
* @author Peli
*/
interface OnColorChangedListener {
/**
* This method is called when the user changed the color.
*
* This works in touch mode, by dragging the along the
* color circle with the finger.
*/
void onColorChanged(View view, int newColor);
/**
* This method is called when the user clicks the center button.
*
* @param colorcircle
* @param newColor
*/
void onColorPicked(View view, int newColor);
}
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