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NAME

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SDLx::LayerManager - Extension for managing layers in a 2D world

CATEGORY

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Extension

SYNOPSIS

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  use SDLx::Layer;
  use SDLx::LayerManager;

  use SDL::Image;
  use SDL::Surface;
  use SDL::Video;

  # creating layers
  my $layer1 = SDLx::Layer->new( SDL::Image::load('image1.png'), {userdata => '7'} );
  my $layer2 = SDLx::Layer->new( SDL::Image::load('image2.png'), 100, 200, {userdata => '42'} );

  # creating the manager that holds the layers
  my $layermanager = SDLx::LayerManager->new();
  $layermanager->add( $layer1 );
  $layermanager->add( $layer2 );

  my $display = # create your video surface here

  $layermanager->blit( $display );

  # accessing the layer at point(x,y)
  print( $layermanager->by_position( 150, 200 )->data->{userdata} ); # should print '42'

DESCRIPTION

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SDLx::LayerManager is a package to handle a bunch of layers. A layer (see SDLx::Layer) is an SDL::Surface, the position of the surface on screen and some additional information.

The layermanager gives you the opportunity to obtain the layer at a given point on screen and get the layers that are ahead or behind a layer.

You will even be able to attach one or more layers to the mouse, e.g. for simulation some drag&drop functionality.

METHODS

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new

  my $layermanager = SDLx::LayerManager->new();

This creates your layermanager object. It doesn't take any parameters.

add

  $layermanager->add( $layer );
  $layermanager->add( SDLx::Layer->new( $surface, $x, $y, $options ) );

Call add to push an SDLx::Layer object to the layermanager.

layers

  my @layers = @{ $layermanager->layers };
  my $first_layer = $layermanager->layers->[0];

The method layers returns all layers that were added before.

layer

  my $layer = $layermanager->layer( $index );

To obtain only one layer at index $index use this function. $index ranges from 0 to lenght - 1.

length

  my $length = $layermanager->length();

This method returns the count of the added layers.

blit

  $layermanager->blit( $surface );

This method blits all layers to the surface (e.g. your video surface).

by_position

  my $layer = $layermanager->by_position( $x, $y );

by_position returns the SDLx::Layer object at point $x $y, which is not fully transparent at this pixel.

ahead

  my @layers = @{ $layermanager->ahead( $index ) };

This method returns all layers that are ahead of the given layer indicated by $index. Ahead means that a layer has a higher z-index and is blitted over the given layer.

Note: This method doesn't check for transparency. This will change in future versions.

behind

  my @layers = @{ $layermanager->behind( $index ) };

This method returns all layers that are behind of the given layer indicated by $index. Behind means that a layer has a lower z-index and is blitted before the given layer.

Note: This method doesn't check for transparency. This will change in future versions.

attach

  $layermanager->attach( $layer,  $x, $y );
  $layermanager->attach( @layers, $x, $y );

This function makes the given layer(s) sticky to the mouse. If you move the mouse the layer(s) will follow. The layermanager blits these layers at last, so they will appear on top of all layers.

$x and $y should be set to the coords of the mouse, e.g. the coords of the mouse click. If you omit $x and $y the layermanager obtains them via SDL::Events::get_mouse_state.

Note: The z-index is not changed for the given layers.

detach_xy

  $layermanager->detach_xy( $x, $y );

detach_xy detaches the prevously attached layers to the given coords. The upper left corner of the backmost layer will be at $x and $y. The other layers are positioned relative to the backmost layer just like before.

detach_back

  $layermanager->detach_back( );

detach_back detaches the prevously attached layers back to the position where they were attached.

foreground

  $layermanager->foreground( $layer );
  $layermanager->foreground( @layers );

This method moves the given layer(s) to the foreground so that they are blittet on top of the other layers.

BUGS

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Report at sdlperl.ath.cx

SUPPORT

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#sdl irc.perl.org

AUTHORS

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COPYRIGHT

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SEE ALSO

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perl(1), SDL(2).

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