/****************************************************************************************
* Copyright (c) 2009 Andrew <andrewdubya@gmail.com> *
* Copyright (c) 2009 Nicolas Raoul <nicolas.raoul@gmail.com> *
* Copyright (c) 2009 Edu Zamora <edu.zasu@gmail.com> *
* *
* This program is free software; you can redistribute it and/or modify it under *
* the terms of the GNU General Public License as published by the Free Software *
* Foundation; either version 3 of the License, or (at your option) any later *
* version. *
* *
* This program is distributed in the hope that it will be useful, but WITHOUT ANY *
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A *
* PARTICULAR PURPOSE. See the GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License along with *
* this program. If not, see <http://www.gnu.org/licenses/>. *
****************************************************************************************/
package com.ichi2.anki;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PathMeasure;
import android.graphics.PointF;
import android.support.v4.content.ContextCompat;
import android.view.Display;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import java.lang.ref.WeakReference;
import java.util.Stack;
/**
* Whiteboard allowing the user to draw the card's answer on the touchscreen.
*/
public class Whiteboard extends View {
private static final float TOUCH_TOLERANCE = 4;
private Paint mPaint;
private UndoStack mUndo = new UndoStack();
private Bitmap mBitmap;
private Canvas mCanvas;
private Path mPath;
private Paint mBitmapPaint;
private WeakReference<AnkiActivity> mActivity;
private float mX;
private float mY;
private boolean mInvertedColors = false;
private boolean mMonochrome = true;
private boolean mUndoModeActive = false;
public Whiteboard(AnkiActivity context, boolean inverted, boolean monochrome) {
super(context, null);
mActivity = new WeakReference<>(context);
mInvertedColors = inverted;
mMonochrome = monochrome;
int foregroundColor;
if (!mInvertedColors) {
if (mMonochrome) {
foregroundColor = Color.BLACK;
} else {
foregroundColor = ContextCompat.getColor(context, R.color.wb_fg_color);
}
} else {
if (mMonochrome) {
foregroundColor = Color.WHITE;
} else {
foregroundColor = ContextCompat.getColor(context, R.color.wb_fg_color_inv);
}
}
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(foregroundColor);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
int wbStrokeWidth = AnkiDroidApp.getSharedPrefs(context).getInt("whiteBoardStrokeWidth", 6);
mPaint.setStrokeWidth((float) wbStrokeWidth);
createBitmap();
mPath = new Path();
mBitmapPaint = new Paint(Paint.DITHER_FLAG);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawColor(0);
canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
canvas.drawPath(mPath, mPaint);
}
/**
* Handle touch screen motion events.
*
* @param event The motion event.
* @return True if the event was handled, false otherwise.
*/
public boolean handleTouchEvent(MotionEvent event) {
float x = event.getX();
float y = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
touchStart(x, y);
invalidate();
return true;
case MotionEvent.ACTION_MOVE:
for (int i = 0; i < event.getHistorySize(); i++) {
touchMove(event.getHistoricalX(i), event.getHistoricalY(i));
}
touchMove(x, y);
invalidate();
return true;
case MotionEvent.ACTION_UP:
touchUp();
invalidate();
return true;
default:
return false;
}
}
/**
* Clear the whiteboard.
*/
public void clear() {
mUndoModeActive = false;
mBitmap.eraseColor(0);
mUndo.clear();
invalidate();
if (mActivity.get() != null) {
mActivity.get().supportInvalidateOptionsMenu();
}
}
/**
* Undo the last stroke
*/
public void undo() {
mUndo.pop();
mUndo.apply();
if (undoSize() == 0 && mActivity.get() != null) {
mActivity.get().supportInvalidateOptionsMenu();
}
}
/**
* @return the number of strokes currently on the undo queue
*/
public int undoSize() {
return mUndo.size();
}
/**
* @return true if the undo queue has had any strokes added to it since the last clear
*/
public boolean isUndoModeActive() {
return mUndoModeActive;
}
private void createBitmap(int w, int h, Bitmap.Config conf) {
mBitmap = Bitmap.createBitmap(w, h, conf);
mCanvas = new Canvas(mBitmap);
clear();
}
private void createBitmap() {
// To fix issue #1336, just make the whiteboard big and square.
int bitmapSize = Math.max(getDisplayWidth(), getDisplayHeight());
if (mMonochrome && !mInvertedColors) {
createBitmap(bitmapSize, bitmapSize, Bitmap.Config.ALPHA_8);
} else {
createBitmap(bitmapSize, bitmapSize, Bitmap.Config.ARGB_4444);
}
}
private void touchStart(float x, float y) {
mPath.reset();
mPath.moveTo(x, y);
mX = x;
mY = y;
}
private void touchMove(float x, float y) {
float dx = Math.abs(x - mX);
float dy = Math.abs(y - mY);
if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
mPath.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);
mX = x;
mY = y;
}
}
private void touchUp() {
PathMeasure pm = new PathMeasure(mPath, false);
mPath.lineTo(mX, mY);
if(pm.getLength() > 0){
mCanvas.drawPath(mPath, mPaint);
mUndo.add(mPath);
} else {
mCanvas.drawPoint(mX, mY, mPaint);
mUndo.add(mX, mY);
}
mUndoModeActive = true;
// kill the path so we don't double draw
mPath.reset();
if (mUndo.size() == 1 && mActivity.get() != null) {
mActivity.get().supportInvalidateOptionsMenu();
}
}
private static int getDisplayHeight() {
Display display = ((WindowManager) AnkiDroidApp.getInstance().getApplicationContext().
getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
return display.getHeight();
}
private static int getDisplayWidth() {
Display display = ((WindowManager) AnkiDroidApp.getInstance().getApplicationContext().
getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
return display.getWidth();
}
/**
* Keep a stack of all points and paths so that the last stroke can be undone
* pop() removes the last stroke from the stack, and apply() redraws it to whiteboard.
*/
private class UndoStack {
private final Stack<Path> mPathStack = new Stack<>();
private final Stack<PointF> mPointStack = new Stack<>();
private final Stack<Integer> mWhichStack = new Stack<>();
public void add(Path path) {
mPathStack.add(new Path(path));
mWhichStack.add(0);
}
public void add(float x, float y) {
mPointStack.add(new PointF(x, y));
mWhichStack.add(1);
}
public void clear() {
mPathStack.clear();
mPointStack.clear();
mWhichStack.clear();
}
public int size() {
return mWhichStack.size();
}
public void pop() {
if (mWhichStack.size() == 0) return;
switch (mWhichStack.peek()) {
case 0:
mPathStack.pop();
break;
case 1:
mPointStack.pop();
break;
}
mWhichStack.pop();
}
public void apply() {
mBitmap.eraseColor(0);
for (Path path : mPathStack) {
mCanvas.drawPath(path, mPaint);
}
for (PointF point : mPointStack) {
mCanvas.drawPoint(point.x, point.y, mPaint);
}
invalidate();
}
}
}