Develop Reference

Item drawn in Custom view onDraw() keeps disappearing

I'm drawing 3 things in my custom view in the onDraw() method: a vector drawable, a simple line and a triangle (made from 4 Points and a Path). This custom view is displayed in a tab.
If I swipe to go to another tab I see that the system calls onDraw(). When I return to the tab holding my custom view the vector drawable and simple line are still visible but the triangle has disappeared. If I now swipe to another tab, onDraw() runs again and back in the tab with the custom view, all items (including the triangle) are now visible. This disappearing/appearing continues to happen as I swipe back and forth. Why is my triangle disappearing?
UPDATE 1 (hacky fix):
I've tried experimenting and notice that when I move my triangle Path object creation out of my init() method and put it directly in the onDraw() method - then all works well, nothing disappears. But, I now get the 'Avoid object allocations during draw' warning as I'm creating this object in onDraw();
UPDATE 2 (better fix?):
After more experimenting, it's definitely the Path causing this problem. Another solution to this - which doesn't incur the 'Avoid object allocations during draw' warning is: keep Path creation in init() and remove the line of code 'myPath.setFillType(Path.FillType.EVEN_ODD)'. It solves my problem, but I've no idea why.
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
// Co-ordinates
int width = getWidth();
int halfWidth = width/2;
int left = 0;
int top = 0;
int centreX = left + halfWidth;
int centreY = top + halfWidth;
int baseSize = Math.round((float)(halfWidth * 0.05));
// Vector drawable - always draws fine!
myVectorDrawable.setBounds(left, top, left + width, top + width);
myVectorDrawable.draw(canvas);
// Simple line - always draws fine!
canvas.drawLine(left, top, 20, 20, paint);
// Triangle - sometimes visible, sometimes disappears!
Point myTriangleBottomMiddle = new Point(centreX, centreY);
Point myTriangleBottomLeft = new Point(centreX, centreY + baseSize);
Point myTriangleBottomRight = new Point(centreX, centreY - baseSize);
Point myTriangleTopMiddle = new Point(centreX + halfWidth, centreY);
myPath.moveTo(myTriangleBottomMiddle.x, myTriangleBottomMiddle.y);
myPath.lineTo(myTriangleBottomLeft.x, mTriangleBottomLeft.y);
myPath.lineTo(myTriangleTopMiddle.x, myTriangleTopMiddle.y);
myPath.lineTo(myTriangleBottomRight.x, myTriangleBottomRight.y);
mPath.close();
canvas.drawPath(myPath, myPaint);
}
Below the code where I set up stuff so as not to burden the onDraw() method.
private void init() {
// Vector drawable
myVectorDrawable = r.getDrawable(R.drawable.gauge_dial);
// Triangle path - ** THIS BEING HERE SEEMS TO BE THE PROBLEM **
myPath = new Path();
myPath.setFillType(Path.FillType.EVEN_ODD);
// Triangle Paint
myPaint = new Paint();
myPaint.setColor(r.getColor(R.color.black));
myPaint.setStrokeWidth(2);
myPaint.setAntiAlias(true);
myPaint.setStyle(Paint.Style.FILL);
// Simple line paint
Paint paint = new Paint();
paint.setColor(Color.BLACK);
}

Add a call to reset() on the path.
// Triangle - sometimes visible, sometimes disappears!
Point myTriangleBottomMiddle = new Point(centreX, centreY);
Point myTriangleBottomLeft = new Point(centreX, centreY + baseSize);
Point myTriangleBottomRight = new Point(centreX, centreY - baseSize);
Point myTriangleTopMiddle = new Point(centreX + halfWidth, centreY);
myPath.reset();
myPath.moveTo(myTriangleBottomMiddle.x, myTriangleBottomMiddle.y);
myPath.lineTo(myTriangleBottomLeft.x, mTriangleBottomLeft.y);
myPath.lineTo(myTriangleTopMiddle.x, myTriangleTopMiddle.y);
myPath.lineTo(myTriangleBottomRight.x, myTriangleBottomRight.y);
mPath.close();
canvas.drawPath(myPath, myPaint);
Also, I would recommend putting the vector drawable into a separate view so it's not redrawn everytime you need to animate the triangle (assuming this is going to be an animated guage dial).

Cocos2d-X: CCDrawNode draw circle/custom shape

I am using CCDrawNode to create mask type effect (not exactly mask). Everything works well but there is one problem that CCDrawNode only draws square and i want to draw it with custom texture/sprite. Is there any solution to it.
Below is my code of using CCDrawNode
// on "init" you need to initialize your instance
bool HelloWorld::init()
{
//////////////////////////////
// 1. super init first
if ( !CCLayer::init() )
{
return false;
}
CCSize visibleSize = CCDirector::sharedDirector()->getVisibleSize();
CCPoint origin = CCDirector::sharedDirector()->getVisibleOrigin();
CCLayer *layer = CCLayer::create();
CCSprite* pSprite = CCSprite::create("HelloWorld.png");
pSprite->setPosition(ccp(visibleSize.width/2 + origin.x, visibleSize.height/2 + origin.y));
layer->addChild(pSprite, 0);
addChild(layer);
//this is the layer that we want to "cut"
CCLayer* layer1 = CCLayerColor::create(ccc4(122, 144, 0, 255), visibleSize.width, visibleSize.height);
this->setTouchEnabled(true);
//we need to create a ccnode, which will be a stencil for ccclipingnode, draw node is a good choice for that
stencil = CCDrawNode::create();
//CCClipingNode show the intersection of stencil and theirs children
CCClippingNode *cliper = CCClippingNode::create(stencil);
cliper->setInverted(true);
cliper->addChild(layer1);
addChild(cliper);
return true;
}
void HelloWorld::ccTouchesMoved(CCSet* touches, CCEvent* event)
{
CCTouch* touch = (CCTouch*)touches->anyObject();
// get start & end location
CCPoint start = touch->getLocationInView();
CCPoint end = touch->getPreviousLocationInView();
// get corrected location
start = CCDirector::sharedDirector()->convertToGL(start);
end = CCDirector::sharedDirector()->convertToGL(end);
//stencil->drawDot(start, 25, ccc4f(0, 0, 0, 255));
stencil->drawSegment(start, end, 25, ccc4f(0, 0, 0, 255));
}

If you want to draw custom texture you should use CCRenderTexture. In order to draw something you should go smthin like this
myRenderTexture->begin();
mySpriteLoadedWithTexture->visit();
myRenderTexture->end();
Also if you want the drawn lines to be smooth you should draw it in loop so that they are placed in equal distance
float distance = ccpDistance(start, end);
for (int i = 0; i < distance; i++)
{
float difx = end.x - start.x;
float dify = end.y - start.y;
float delta = (float)i / distance;
m_brush->setPosition(CCPoint(start.x + (difx * delta), start.y + (dify * delta)));
m_brush->visit();
}
Hope it helps

ShowCaseView circle size

Is it possible to change the current size of circle in ShowCaseView?
What I have in my code is the following:
ShowcaseView.ConfigOptions co = new ShowcaseView.ConfigOptions();
co.hideOnClickOutside = false;
return ShowcaseView.insertShowcaseView(id, activity, title, message, co);
but right now, I'm just showing the default size of ShowCaseView, How can I resize it if so?
thanks!
for more info regarding ShowCaseView, this will be of help..
https://github.com/amlcurran/Showcaseview

I found how to do it, we have to do some changes in the code.
I'm writing this answer while current ShowcaseView release is 5.0
A) scalemultiplier became orphelin, we have to reimplement it.
1) open StandarShowcaseDrawer.java, locate drawShowcase method and modify it as bellow :
#Override
public void drawShowcase(Bitmap buffer, float x, float y, float scaleMultiplier) {
Canvas bufferCanvas = new Canvas(buffer);
//[GIOVA]
//To avoid an infinite exception
if(scaleMultiplier == 0.0f)
scaleMultiplier = 0.001f;
//[/GIOVA]
//[Original]
//bufferCanvas.drawCircle(x, y, showcaseRadius, eraserPaint);
//[/Original]
//[GIOVA]
bufferCanvas.drawCircle(x, y, showcaseRadius * scaleMultiplier, eraserPaint);
//[/GIOVA]
int halfW = getShowcaseWidth() / 2;
int halfH = getShowcaseHeight() / 2;
int left = (int) (x - halfW);
int top = (int) (y - halfH);
showcaseDrawable.setBounds(left, top,
left + getShowcaseWidth(),
top + getShowcaseHeight());
showcaseDrawable.draw(bufferCanvas);
}
NB : note that i've placed some [GIOVA] and [Original] tags, so you can compare changes ;)
2) open NewShowcaseDrawer.java, same job as previous step :
#Override
public void drawShowcase(Bitmap buffer, float x, float y, float scaleMultiplier) {
Canvas bufferCanvas = new Canvas(buffer);
//[GIOVA]
//To avoid an infinite exception
if(scaleMultiplier == 0.0f)
scaleMultiplier = 0.001f;
//[/GIOVA]
eraserPaint.setAlpha(ALPHA_60_PERCENT);
//[Original]
//bufferCanvas.drawCircle(x, y, outerRadius , eraserPaint);
//eraserPaint.setAlpha(0);
//bufferCanvas.drawCircle(x, y, innerRadius , eraserPaint);
//[/Original]
//[GIOVA]
bufferCanvas.drawCircle(x, y, outerRadius * scaleMultiplier, eraserPaint);
eraserPaint.setAlpha(0);
bufferCanvas.drawCircle(x, y, innerRadius * scaleMultiplier, eraserPaint);
//[/GIOVA]
}
B) Now we need to be able to set the value, we'll add a method to the builder.
Open ShowcaseView.java then locate following line :
public static class Builder {
Inside this Builder class, add the following method :
public Builder setScaleMultiplier(float multiplier){
showcaseView.setScaleMultiplier(multiplier);
return this;
}
How to use it :
Pretty simple now, in your activity, when you use Builder to setup your showcaseview, simply call setScaleMultiplier.
Example :
sv = new ShowcaseView.Builder(this, true)
.setTarget(target)
.setContentTitle(getResources().getString(R.string.welcome))
.setContentText(getResources().getString(R.string.welcomDescription))
.setStyle(R.style.MyTheme)
.setScaleMultiplier(0.3f)
.build();
sv.Show();

Use setScaleMultiplier(float scaleMultiplier)
Hope help you!

Collision ImageViews not working

I'm trying to generate random ImageViews on a Layout without the ImageViews intersecting each other. I'm generating a random point within the screen dimensions like this:
private Point generateRandomLocation(Point dimensions) {
Random random = new Random();
// generate random x
int x = random.nextInt((dimensions.x - 0) + 1);
// generate random y
int y = random.nextInt((dimensions.y - 0) + 1);
Point location = new Point(x, y);
if(!collision(location)) {
return new Point(x, y);
} else {
return generateRandomLocation(dimensions);
}
}
The collision method contains the following method to determine wether the ImageViews collide or not. BubbleImage is a simple extension of ImageView.
private boolean collision(Point location) {
// takes 100 as inital width & height
int x_1 = location.x;
int y_1 = location.y;
int x_2;
int y_2;
boolean collided = false;
// get all bubbleimages
for (int i = 0; i < mainLayout.getChildCount(); i++) {
View childView = mainLayout.getChildAt(i);
if (childView instanceof BubbleImage) {
x_2 = (int) childView.getX();
y_2 = (int) childView.getY();
// create rectangles
Rect rect1 = new Rect(x_1, y_1, x_1 + 100, y_1 - 100);
Rect rect2 = new Rect(x_2, y_2, x_2 + 100, y_2 - 100);
collided = Rect.intersects(rect1, rect2);
}
}
return collided;
}
Anyone spotting the faulty logic here?
Edit: Rect.intersects() seems to be returning false, even when the imageviews are intersecting.

When creating new Rects rect1 & rect2, the constructor is Rect(left, top, right, bottom). E.g. Rect(10, 10, 20, 20), because android screen origin is in the top left corner.
You have created the Rects in a wrong way, as Rect(left, bottom, right, top). Try switching the 2nd and 4th parameters in the constructor calls, or increase the 4th parameter to be bigger than 2nd.
Like this:
Rect rect1 = new Rect(x_1, y_1, x_1 + 100, y_1 + 100);

Adding Endless parallax background in cocos2d android

I am working on CoCos2d with android.I want to add an endless scrolling background to my Screen by using CCParallaxNode.
I am able to add background and move it but after the completion of that move action the screen goes black.
Can someone help me out?
My code is
CCParallaxNode parallaxNode;
CCSprite spacedust1;
CCSprite spacedust2;
CCSprite planetsunrise;
CCSprite galaxy;
CCSprite spacialanomaly;
CCSprite spacialanomaly2;
parallaxNode = CCParallaxNode.node();
spacedust1 = CCSprite.sprite("bg_front_spacedust.png");
spacedust2 = CCSprite.sprite("bg_front_spacedust.png");
planetsunrise = CCSprite.sprite("bg_planetsunrise.png");
galaxy = CCSprite.sprite("bg_galaxy.png");
spacialanomaly = CCSprite.sprite("bg_spacialanomaly.png");
spacialanomaly2 = CCSprite.sprite("bg_spacialanomaly2.png");
// 3) Determine relative movement speeds for space dust and background
// CGPoint cgPoint = CGPoint.ccp(0.1, 0.1);
CGPoint dustSpeed = CGPoint.ccp(10, 10);
CGPoint bgSpeed = CGPoint.ccp(5, 5);
// CGPoint bgSpeed = ccp(0.05, 0.05);
parallaxNode.addChild(spacedust1, 0, dustSpeed.x, dustSpeed.y, 0,
winSize.height / 2);
parallaxNode.addChild(spacedust2, 0, dustSpeed.x, dustSpeed.y,
spacedust1.getContentSize().width, winSize.height / 2);
parallaxNode.addChild(galaxy, -1, bgSpeed.x, bgSpeed.y, 0, 10);
parallaxNode.addChild(planetsunrise, -1, bgSpeed.x, bgSpeed.y, 600, 5);
parallaxNode
.addChild(spacialanomaly, -1, bgSpeed.x, bgSpeed.y, 900, 20);
parallaxNode.addChild(spacialanomaly2, -1, bgSpeed.x, bgSpeed.y, 1500,
30);
CCIntervalAction go = CCMoveBy.action(4, CGPoint.ccp(winSize.width, 0));
CCIntervalAction goBack = go.reverse();
CCIntervalAction seq = CCSequence.actions(go, goBack);
CCRepeatForever action = CCRepeatForever.action(goBack);
parallaxNode.runAction(action);

I see that since not a single answer worked for you. I will provide a simple code which will help you for your parralax scrolling background.
Add this code in your game layers constructor
background1 = CCSprite.sprite("bg2.png");
background2 = CCSprite.sprite("bg2.png");
background1.setPosition(CGPoint.ccp(winSize.width*0.5f,winSize.height*0.5f));
addChild(background1);
background2.setPosition(CGPoint.ccp(winSize.width+winSize.width*0.5f,winSize.height*0.5f));
addChild(background2);
and a scroll method which is scheduled every millisecond.
add this in constructor
this.schedule("scroll");
and now the scroll method.
public void scroll(float dt) {
CGPoint pos1 = background1.getPosition();
CGPoint pos2 = background2.getPosition();
pos1.x -= 5.0f;
pos2.x -= 5.0f;
if(pos1.x <=-(winSize.width*0.5f) )
{
pos1.x = pos2.x + winSize.width;
}
if(pos2.x <=-(winSize.width*0.5f) )
{
pos2.x = pos1.x + winSize.width;
}
background1.setPosition(pos1);
background2.setPosition(pos2);
}
mark my answer if it worked.

Call this method from the class Constructor. I found this trick from Example : "shotingblock-master" available on github...
private void endlessBackground() {
// Create the two background sprites which will alternate
_oddBackground = CCSprite.sprite("blue_background.png");
_evenBackground = CCSprite.sprite("blue_background.png");
// One starts dead centre and one starts exactly one screen height above
oddBackground.setPosition(_winSize.width / 2, _winSize.height / 2);
evenBackground.setPosition(_winSize.width / 2, _winSize.height
+ (_winSize.height / 2));
// Schedule the scrolling action
schedule("scroll");
// Add sprites to the layer
addChild(_oddBackground).addChild(_evenBackground);
}
public void scroll(float dt) {
// move them 100*dt pixels down
_oddBackground.setPosition(_oddBackground.getPosition().x,
_oddBackground.getPosition().y - 150 * dt);
_evenBackground.setPosition(_evenBackground.getPosition().x,
_evenBackground.getPosition().y - 150 * dt);
// reset position when they are off from view.
if (_oddBackground.getPosition().y < -_winSize.height / 2) {
_oddBackground.setPosition(_winSize.width / 2, _winSize.height / 2);
_evenBackground.setPosition(_winSize.width / 2, _winSize.height
+ (_winSize.height / 2));
}
}
}
IT works excellent in my case. May be it'll help full for you.

try using this:
CCTexture2D *texture = CCTextureCache::sharedTextureCache()->addImage("pic.png");
ccTexParams params = {GL_LINEAR, GL_LINEAR, GL_REPEAT, GL_REPEAT};
texture->setTexParameters(&params);
CCSprite *sprite = CCSprite::spriteWithTexture(texture, CCRectMake(0, 0, 90, 90));
and make sure that The image's height and width must be power of 2.

It looks like the CCRepeatForever action is only running it goBack, which means that it's not reversing. Try the following:
CCIntervalAction go = CCMoveBy.action(4, CGPoint.ccp(winSize.width, 0));
CCIntervalAction goBack = go.reverse();
CCIntervalAction seq = CCSequence.actions(go, goBack);
CCRepeatForever action = CCRepeatForever.action(seq); // change to seq instead of goBack
parallaxNode.runAction(action);

This is trick for make it happen. You can Use the large png and working on it or check the sample test code which is available in coocs2d-android library
CCSprite background = CCSprite.sprite("background.png");
// create a void node, a parent node
CCParallaxNode voidNode = CCParallaxNode.node();
// background image is moved at a ratio of 0.4x, 0.5y
voidNode.addChild(background, -1, 0.4f, 0.5f, 0, 0);
// write your own code for the parallax node
CCIntervalAction goUp = CCMoveBy.action(4, CGPoint.make(0,-200));
CCIntervalAction goDown = goUp.reverse();
CCIntervalAction go = CCMoveBy.action(8, CGPoint.make(-1000, 0));
CCIntervalAction goBack = go.reverse();
CCIntervalAction seq = CCSequence.actions(goUp, go, goDown, goBack);
voidNode.runAction(CCRepeatForever.action(seq));
addChild(voidNode);

Please check out below link for Parallax vertical endless background:
http://kalpeshsantoki.blogspot.in/2014/07/create-vertical-endless-parallax.html
CGSize winSize = CCDirector.sharedDirector().displaySize();
//I made graphics for screen 720*1200....so I made this dynamic scale to support multiple screens
float sX = winSize.width / 720.0f;
float sY = winSize.height / 1200.0f;
background = CCVerticalParallaxNode.node(sX, sY, true);
background.addEntity(1f, "background.png", 0);
background.addEntity(3, "road_simple.png", winSize.width / 2);
background.addEntity(1.7f, "road_side.png", 0);
addChild(background);