package com.roboo.like.netease.view;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.SweepGradient;
import android.os.Bundle;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import com.roboo.like.netease.R;
/**
* Displays a holo-themed color picker.
*
* <p>
* Use {@link #getColor()} to retrieve the selected color.
* </p>
*/
public class ColorPickerView extends View {
/*
* Constants used to save/restore the instance state.
*/
private static final String STATE_PARENT = "parent";
private static final String STATE_ANGLE = "angle";
/**
* Colors to construct the color wheel using {@link SweepGradient}.
*
* <p>
* Note: The algorithm in {@link #normalizeColor(int)} highly depends on these exact values. Be
* aware that {@link #setColor(int)} might break if you change this array.
* </p>
*/
private static final int[] COLORS = new int[] { 0xFFFF0000, 0xFFFF00FF, 0xFF0000FF, 0xFF00FFFF,
0xFF00FF00, 0xFFFFFF00, 0xFFFF0000 };
/**
* Get a random color.
*
* @return The ARGB value of a randomly selected color.
*/
public static int getRandomColor() {
return calculateColor((float) (Math.random() * 2 * Math.PI));
}
private static int ave(int s, int d, float p) {
return s + java.lang.Math.round(p * (d - s));
}
/**
* Calculate the color using the supplied angle.
*
* @param angle
* The selected color's position expressed as angle (in rad).
*
* @return The ARGB value of the color on the color wheel at the specified angle.
*/
private static int calculateColor(float angle) {
float unit = (float) (angle / (2 * Math.PI));
if (unit < 0) {
unit += 1;
}
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;
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);
}
/**
* {@code Paint} instance used to draw the color wheel.
*/
private Paint mColorWheelPaint;
/**
* {@code Paint} instance used to draw the pointer's "halo".
*/
private Paint mPointerHaloPaint;
/**
* {@code Paint} instance used to draw the pointer (the selected color).
*/
private Paint mPointerColor;
/**
* The stroke width used to paint the color wheel (in pixels).
*/
private int mColorWheelStrokeWidth;
/**
* The radius of the pointer (in pixels).
*/
private int mPointerRadius;
/**
* The rectangle enclosing the color wheel.
*/
private RectF mColorWheelRectangle = new RectF();
/**
* {@code true} if the user clicked on the pointer to start the move mode. {@code false} once
* the user stops touching the screen.
*
* @see #onTouchEvent(MotionEvent)
*/
private boolean mUserIsMovingPointer = false;
/**
* Number of pixels the origin of this view is moved in X- and Y-direction.
*
* <p>
* We use the center of this (quadratic) View as origin of our internal coordinate system.
* Android uses the upper left corner as origin for the View-specific coordinate system. So this
* is the value we use to translate from one coordinate system to the other.
* </p>
*
* <p>Note: (Re)calculated in {@link #onMeasure(int, int)}.</p>
*
* @see #onDraw(Canvas)
*/
private float mTranslationOffset;
/**
* Radius of the color wheel in pixels.
*
* <p>Note: (Re)calculated in {@link #onMeasure(int, int)}.</p>
*/
private float mColorWheelRadius;
/**
* The pointer's position expressed as angle (in rad).
*/
private float mAngle;
public ColorPickerView(Context context) {
super(context);
init(null, 0);
}
public ColorPickerView(Context context, AttributeSet attrs) {
super(context, attrs);
init(attrs, 0);
}
public ColorPickerView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init(attrs, defStyle);
}
private void init(AttributeSet attrs, int defStyle) {
final TypedArray a = getContext().obtainStyledAttributes(attrs,
R.styleable.ColorPicker, defStyle, 0);
mColorWheelStrokeWidth = a.getInteger(R.styleable.ColorPicker_wheel_size, 16);
mPointerRadius = a.getInteger(R.styleable.ColorPicker_pointer_size, 48);
a.recycle();
Shader s = new SweepGradient(0, 0, COLORS, null);
mColorWheelPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mColorWheelPaint.setShader(s);
mColorWheelPaint.setStyle(Paint.Style.STROKE);
mColorWheelPaint.setStrokeWidth(mColorWheelStrokeWidth);
mPointerHaloPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mPointerHaloPaint.setColor(Color.BLACK);
mPointerHaloPaint.setStrokeWidth(5);
mPointerHaloPaint.setAlpha(0x60);
mPointerColor = new Paint(Paint.ANTI_ALIAS_FLAG);
mPointerColor.setStrokeWidth(5);
mAngle = (float) (-Math.PI / 2);
mPointerColor.setColor(calculateColor(mAngle));
}
@Override
protected void onDraw(Canvas canvas) {
// All of our positions are using our internal coordinate system. Instead of translating
// them we let Canvas do the work for us.
canvas.translate(mTranslationOffset, mTranslationOffset);
// Draw the color wheel.
canvas.drawOval(mColorWheelRectangle, mColorWheelPaint);
float[] pointerPosition = calculatePointerPosition(mAngle);
// Draw the pointer's "halo"
canvas.drawCircle(pointerPosition[0], pointerPosition[1], mPointerRadius, mPointerHaloPaint);
// Draw the pointer (the currently selected color) slightly smaller on top.
canvas.drawCircle(pointerPosition[0], pointerPosition[1],
(float) (mPointerRadius / 1.2), mPointerColor);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int height = getDefaultSize(getSuggestedMinimumHeight(),
heightMeasureSpec);
int width = getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec);
int min = Math.min(width, height);
setMeasuredDimension(min, min);
mTranslationOffset = min * 0.5f;
mColorWheelRadius = mTranslationOffset - mPointerRadius;
mColorWheelRectangle.set(-mColorWheelRadius, -mColorWheelRadius, mColorWheelRadius,
mColorWheelRadius);
}
/**
* Get the currently selected color.
*
* @return The ARGB value of the currently selected color.
*/
public int getColor() {
return calculateColor(mAngle);
}
/**
* Set the color to be highlighted by the pointer.
*
* @param color
* The RGB value of the color to highlight. If this is not a color displayed on the
* color wheel a very simple algorithm is used to map it to the color wheel. The
* resulting color often won't look close to the original color. This is especially true
* for shades of grey. You have been warned!
*/
public void setColor(int color) {
mAngle = colorToAngle(color);
mPointerColor.setColor(calculateColor(mAngle));
invalidate();
}
/**
* Convert a color to an angle.
*
* @param color
* The RGB value of the color to "find" on the color wheel. {@link #normalizeColor(int)}
* will be used to map this color to one on the color wheel if necessary.
*
* @return The angle (in rad) the "normalized" color is displayed on the color wheel.
*/
private float colorToAngle(int color) {
int[] colorInfo = normalizeColor(color);
int normColor = colorInfo[0];
int colorMask = colorInfo[1];
int shiftValue = colorInfo[2];
int anchorColor = (normColor & ~colorMask);
// Find the "anchor" color in the COLORS array
for (int i = 0; i < COLORS.length - 1; i++) {
if (COLORS[i] == anchorColor) {
int nextValue = COLORS[i + 1];
double value;
double decimals = ((normColor >> shiftValue) & 0xFF) / 255D;
// Find out if the gradient our color belongs to goes from the element just found to
// the next element in the array.
if ((nextValue & colorMask) != (anchorColor & colorMask)) {
// Compute value depending of the gradient direction
if (nextValue < anchorColor) {
value = i + 1 - decimals;
} else {
value = i + decimals;
}
} else {
// It's a gradient from this element to the previous element in the array.
// Wrap to the end of the array if the "anchor" color is the first element.
int index = (i == 0) ? COLORS.length - 1 : i;
int prevValue = COLORS[index - 1];
// Compute value depending of the gradient direction
if (prevValue < anchorColor) {
value = index - 1 + decimals;
} else {
value = index - decimals;
}
}
// Calculate the angle in rad (from -PI to PI)
float angle = (float) (2 * Math.PI * value / (COLORS.length - 1));
if (angle > Math.PI) {
angle -= 2 * Math.PI;
}
return angle;
}
}
// This shouldn't happen
return 0;
}
/**
* "Normalize" the supplied color.
*
* <p>
* This will set the lowest value of R,G,B to 0, the highest to 255, and will keep the middle
* value.<br>
* For values close to those on the color wheel this will result in close matches. For other
* values, especially shades of grey this will produce funny results.
* </p>
*
* @param color
* The color to "normalize".
*
* @return An {@code int} array with the following contents:
* <ol>
* <li>The ARGB value of the "normalized" color.</li>
* <li>A mask with all bits {@code 0} but those for the byte representing the
* "middle value" that remains unchanged in the "normalized" color.</li>
* <li>The number of bits the "normalized" color has to be shifted to the right so the
* "middle value" is in the lower 8 bits.</li>
* </ol>
*/
private int[] normalizeColor(int color) {
int red = Color.red(color);
int green = Color.green(color);
int blue = Color.blue(color);
int newRed = red;
int newGreen = green;
int newBlue = blue;
int maskRed = 0;
int maskGreen = 0;
int maskBlue = 0;
int shiftValue;
if (red < green && red < blue) {
// Red is the smallest component
newRed = 0;
if (green > blue) {
// Green is the largest component
shiftValue = 0;
maskBlue = 0xFF;
newGreen = 0xFF;
} else {
// We make blue the largest component
shiftValue = 8;
maskGreen = 0xFF;
newBlue = 0xFF;
}
} else if (green < red && green < blue) {
// Green is the smallest component
newGreen = 0;
if (red > blue) {
// Red is the largest component
shiftValue = 0;
maskBlue = 0xFF;
newRed = 0xFF;
} else {
// We make blue the largest component
shiftValue = 16;
maskRed = 0xFF;
newBlue = 0xFF;
}
} else {
// We make blue the smallest component
newBlue = 0;
if (red > green) {
// Red is the largest component
shiftValue = 8;
maskGreen = 0xFF;
newRed = 0xFF;
} else {
// We make green the largest component
shiftValue = 16;
maskRed = 0xFF;
newGreen = 0xFF;
}
}
int normColor = Color.argb(255, newRed, newGreen, newBlue);
int colorMask = Color.argb(0, maskRed, maskGreen, maskBlue);
return new int[] { normColor, colorMask, shiftValue };
}
@Override
public boolean onTouchEvent(MotionEvent event) {
// Convert coordinates to our internal coordinate system
float x = event.getX() - mTranslationOffset;
float y = event.getY() - mTranslationOffset;
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
// Check whether the user pressed on (or near) the pointer
float[] pointerPosition = calculatePointerPosition(mAngle);
if (x >= (pointerPosition[0] - 48) && x <= (pointerPosition[0] + 48)
&& y >= (pointerPosition[1] - 48) && y <= (pointerPosition[1] + 48)) {
mUserIsMovingPointer = true;
invalidate();
}
break;
case MotionEvent.ACTION_MOVE:
if (mUserIsMovingPointer) {
mAngle = (float) java.lang.Math.atan2(y, x);
mPointerColor.setColor(calculateColor(mAngle));
invalidate();
}
break;
case MotionEvent.ACTION_UP:
mUserIsMovingPointer = false;
break;
}
return true;
}
/**
* Calculate the pointer's coordinates on the color wheel using the supplied angle.
*
* @param angle
* The position of the pointer expressed as angle (in rad).
*
* @return The coordinates of the pointer's center in our internal coordinate system.
*/
private float[] calculatePointerPosition(float angle) {
float x = (float) (mColorWheelRadius * Math.cos(angle));
float y = (float) (mColorWheelRadius * Math.sin(angle));
return new float[] { x, y };
}
@Override
protected Parcelable onSaveInstanceState() {
Parcelable superState = super.onSaveInstanceState();
Bundle state = new Bundle();
state.putParcelable(STATE_PARENT, superState);
state.putFloat(STATE_ANGLE, mAngle);
return state;
}
@Override
protected void onRestoreInstanceState(Parcelable state) {
Bundle savedState = (Bundle) state;
Parcelable superState = savedState.getParcelable(STATE_PARENT);
super.onRestoreInstanceState(superState);
mAngle = savedState.getFloat(STATE_ANGLE);
mPointerColor.setColor(calculateColor(mAngle));
}
}