Code Samples

To arouse your curiosity, here are a few examples showing how to use Sparrow. The following is pure Objective-C and shows how to make use of some Sparrow features. We hope this code looks as simple and logical for you as it does for us! (For a thorough look at the features shown below, have a look at the Introduction to Sparrow!)

Create and display an image

// load image
SPImage *image = [SPImage imageWithContentsOfFile:@"image.png"];

// change things like scaling, rotation, etc.
image.scaleX = 2.0f;
image.rotation = PI / 2.0f;
image.x = 40;

// display image
[self addChild:image];

Load a texture from your texture atlas

SPTextureAtlas *atlas =
    [SPTextureAtlas atlasWithContentsOfFile:@"atlas.xml"];
SPImage *image = [SPImage imageWithTexture:
     [atlas textureByName:@"atlas_image"]];

Grouping objects together in a sprite (a DisplayObjectContainer)

SPSprite *sprite = [SPSprite sprite];

// create children
SPImage *venus = [SPImage imageWithContentsOfFile:@"venus.png"];
SPImage *mars = [SPImage imageWithContentsOfFile:@"mars.png"];

// move children to some relative positions
venus.x = 50;
mars.x = -20;

// add children to the sprite
[sprite addChild:venus];
[sprite addChild:mars];

// calculate total width of all children
float totalWidth = sprite.width;

// rotate the whole group
sprite.rotation = PI;

React to touch events

// e.g. in 'init'
[self addEventListener:@selector(onTouchEvent:) atObject:self
    forType:SP_EVENT_TYPE_TOUCH];

// the corresponding listener:
- (void)onTouchEvent:(SPTouchEvent*)event
{
    NSArray *touches = [[event touchesWithTarget:self
        andPhase:SPTouchPhaseMoved] allObjects];
    if (touches.count == 1)
    {
        // one finger touching
        SPTouch *touch = [touches objectAtIndex:0];
        SPPoint *currentPos = [touch locationInSpace:self.parent];
        SPPoint *previousPos =
            [touch previousLocationInSpace:self.parent];
        // ...
    }
    else if (touches.count >= 2)
    {
        // two fingers touching
        // ...
    }
}

Create a simple textfield using one of the iPhone’s standard fonts

// create the text field
SPTextField *textField = [SPTextField textFieldWithText:@"blah!"];

// set things like fontname, size, etc.
textField.fontName = @"Georgia-Bold";
textField.fontSize = 18;
textField.color = 0xaaaaff; //0xRRGGBB
textField.hAlign = SPHAlignCenter; // horizontal alignment
textField.vAlign = SPVAlignCenter; // vertical alignment

// add it to the display list!
[self addChild:textField];

Now use a textfield with a custom bitmap font

// e.g. during startup; file contains coordinates of chars
// and image filename
[SPTextField registerBitmapFontFromFile:@"mouse.fnt"];

// then, anywhere else:
SPTextField *bmpFontTF = [SPTextField textFieldWithWidth:300
    height:120 text:@"Text drawn with a bitmap font"];
bmpFontTF.fontName = @"mouse"; // name set in the fnt-file

Animate anything!

// we want to animate the image that was created above
SPTween *tween = [SPTween tweenWithTarget:image time:5.0f
                               transition:SP_TRANSITION_EASE_IN];

// you can animate any property as long as it's numeric (float,
// double, int). It is animated from it's current value to
// a target value.
[tween animateProperty:@"x" targetValue:310];
[tween animateProperty:@"scaleY" targetValue:0.5];
[tween animateProperty:@"rotation" targetValue:PI_HALF];

// the so-called "juggler" will carry out the tween for you.
[self.stage.juggler addObject:tween];

Can you say that louder, please?!

// the one-liner to play sound
[[SPSound soundWithContentsOfFile:@"sound.aif"] play];

// or the advanced way, with more control:
SPSound *sound = [SPSound soundWithContentsOfFile:@"sound.caf"];
SPSoundChannel *channel = [sound createChannel];
[channel play];