/*
* Copyright 2014 Frakbot (Sebastiano Poggi and Francesco Pontillo)
*
* 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.marshalchen.common.uimodule.simplemodule;
import android.content.Context;
import android.content.res.ColorStateList;
import android.content.res.TypedArray;
import android.graphics.Camera;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.text.Layout;
import android.text.StaticLayout;
import android.text.TextPaint;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.widget.TextView;
import com.marshalchen.common.uimodule.R;
/**
* Implements a Star Wars-like credits roll.
*/
public class CreditsRollView extends TextView {
/** Epsilon used to determine if two float values are equal */
private static final float FLOAT_EPSILON = 0.001f;
private int mPaddingLeft;
private int mPaddingTop;
private int mPaddingRight;
private int mPaddingBottom;
private int mTextColor = 0xffffc92a; // Default: yellow!
private float mAngle = 60f;
private float mScrollPosition = 0f;
private float mEndScrollMult = 2f;
private float mDistanceFromText = 0f;
private final Camera mCamera = new Camera();
private Matrix mMatrix = new Matrix();
private TextPaint mTextPaint;
private StaticLayout mTextLayout;
public CreditsRollView(Context context) {
super(context);
init(null, 0, context);
}
public CreditsRollView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CreditsRollView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init(attrs, defStyle, context);
}
private void init(AttributeSet attrs, int defStyle, Context context) {
// Load attributes
final TypedArray a = context.obtainStyledAttributes(
attrs, R.styleable.CreditsRollView, defStyle, 0);
if (a != null) {
final int N = a.getIndexCount();
for (int i = 0; i < N; ++i) {
int attr = a.getIndex(i);
if (attr == R.styleable.CreditsRollView_angle) {
float angle = a.getFloat(attr, mAngle);
setAngle(angle);
}
else if (attr == R.styleable.CreditsRollView_scrollPosition) {
float scrollPercent = a.getFloat(attr, 0f);
setScrollPosition(scrollPercent);
}
else if (attr == R.styleable.CreditsRollView_endScrollMultiplier) {
float scrollMult = a.getFloat(attr, 0f);
setEndScrollMult(scrollMult);
}
else if (attr == R.styleable.CreditsRollView_distanceFromText) {
float distance = a.getFloat(attr, 0f);
setDistanceFromText(distance);
}
}
a.recycle();
}
initTextPaint();
}
private void initTextPaint() {
mTextPaint = new TextPaint();
// Set up a default TextPaint object
mTextPaint.setFlags(Paint.ANTI_ALIAS_FLAG);
// Update TextPaint and text measurements
mTextPaint.setTextSize(getTextSize());
mTextPaint.setColor(mTextColor);
}
/**
* Gets the current scrolling percentage.
*
* @return Returns the current scrolling position, in the
* [0, 1] range.
*/
public float getScrollPosition() {
return mScrollPosition;
}
/**
* Sets the scroll position for this view.
*
* @param scrollPosition The new scrolling position, in the
* [0, 1] range.
*/
public void setScrollPosition(float scrollPosition) {
if (scrollPosition < 0f) {
scrollPosition = 0f;
}
else if (scrollPosition > 1f) {
scrollPosition = 1f;
}
// Only invalidate if really necessary
if (Math.abs(mScrollPosition - scrollPosition) > FLOAT_EPSILON) {
mScrollPosition = scrollPosition;
invalidate();
}
}
/**
* Gets the credits roll text tilting angle, on the
* X axis.
*
* @return The X-axis tilting angle, in degrees.
*/
public float getAngle() {
return mAngle;
}
/**
* Sets the credits roll text tilting angle, on the
* X axis.
*
* @param angle The X-axis tilting angle, in degrees.
*/
public void setAngle(float angle) {
if (Math.abs(mAngle - angle) > FLOAT_EPSILON) {
mAngle = angle;
invalidate();
}
}
/**
* Gets the end scrolling multiplier value.
*
* @return Returns the end scrolling multiplier.
*/
public float getEndScrollMult() {
return mEndScrollMult;
}
/**
* Sets the end scrolling multiplier value.
* This value is multiplied by the available height of the View
* (that is, {@link #getHeight()} less the top/bottom paddings)
* and used to offset the end scrolling point. Adjust this to
* have the text scrolling end in the desired position.
* Depending on the angle value, you may need to set this to 2,
* 3 or more to have the text get scrolled completely out of
* view.
*
* @param endScrollMult The end scrolling multiplier.
*
* @see #setAngle(float)
*/
public void setEndScrollMult(float endScrollMult) {
if (Math.abs(mEndScrollMult - endScrollMult) > FLOAT_EPSILON) {
mEndScrollMult = endScrollMult;
invalidate();
}
}
/**
* Gets the virtual camera's distance from the text, on
* the Z axis (depth).
*
* @return Returns the camera distance from the text.
*/
public float getDistanceFromText() {
return mDistanceFromText;
}
/**
* Sets the virtual camera's distance from the text, on
* the Z axis (depth).
* <p/>
* The default distance is <code>0</code>. You can increase
* it to "zoom out" from the text, or decrease to "zoom in" to
* the text.
*
* @param distanceFromText The camera distance from the text.
*/
public void setDistanceFromText(float distanceFromText) {
mDistanceFromText = distanceFromText;
}
@Override
protected void onDraw(Canvas canvas) {
mPaddingLeft = getPaddingLeft();
mPaddingTop = getPaddingTop();
mPaddingRight = getPaddingRight();
mPaddingBottom = getPaddingBottom();
final CharSequence text = getText();
if (TextUtils.isEmpty(text)) {
return;
}
int contentWidth = getWidth() - mPaddingLeft - mPaddingRight;
int contentHeight = getHeight() - mPaddingTop - mPaddingBottom;
final int saveCnt = canvas.save();
// Rotate/translate the camera
canvas.getMatrix(mMatrix);
mCamera.save();
int cX = contentWidth / 2 + mPaddingLeft;
int cY = contentHeight / 2 + mPaddingTop;
mCamera.rotateX(mAngle);
mCamera.translate(0, 0, mDistanceFromText);
mCamera.getMatrix(mMatrix);
mMatrix.preTranslate(-cX, -cY);
mMatrix.postTranslate(cX, cY);
mCamera.restore();
canvas.concat(mMatrix);
// The end scroll multiplier ensures that the text scrolls completely out of view
canvas.translate(0f, contentHeight - mScrollPosition *
(mTextLayout.getHeight() + mEndScrollMult * contentHeight));
// Draw the text
mTextLayout.draw(canvas);
canvas.restoreToCount(saveCnt);
}
@Override
public void setText(CharSequence text, BufferType type) {
super.setText(text, type);
if (mTextPaint == null) {
initTextPaint();
}
measureAndLayoutText(text);
}
@Override
public void setTextColor(int color) {
super.setTextColor(color);
mTextColor = color;
initTextPaint();
}
@Override
public void setTextColor(ColorStateList colors) {
super.setTextColor(colors);
if (!colors.isStateful()) {
mTextColor = colors.getDefaultColor();
}
else {
mTextColor = colors.getColorForState(getDrawableState(), colors.getDefaultColor());
}
initTextPaint();
invalidate();
}
@Override
public void setTextSize(float size) {
super.setTextSize(size);
initTextPaint();
invalidate();
}
@Override
public void setTextSize(int unit, float size) {
super.setTextSize(unit, size);
initTextPaint();
invalidate();
}
@Override
public void setTextAppearance(Context context, int resid) {
super.setTextAppearance(context, resid);
initTextPaint();
invalidate();
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
// Measure and layout the text
final CharSequence text = getText();
measureAndLayoutText(text);
}
private void measureAndLayoutText(CharSequence text) {
if (TextUtils.isEmpty(text)) {
mTextLayout = null;
return;
}
int availableWidth = getWidth() - mPaddingLeft - mPaddingRight;
mTextLayout = new StaticLayout(text, mTextPaint, availableWidth, Layout.Alignment.ALIGN_CENTER,
1.1f, 0f, true);
}
}