SDLx::Layer

Section: User Contributed Perl Documentation (3)
Updated: 2019-07-26
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NAME

SDLx::Layer - Storage object for surface and position information  

CATEGORY

Extension  

SYNOPSIS

  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
  
  $layer1->foreground;
  printf( "%s\n", $layer1->behind->[0]->data->{userdata} ); # prints 42

 

DESCRIPTION

A layer (see SDLx::Layer) is an SDL::Surface, the position of the surface on screen and some additional information, e.g. ingame states.  

METHODS

 

new

  my $layer = SDLx::Layer->new( $surface );
  my $layer = SDLx::Layer->new( $surface,                                   %data );
  my $layer = SDLx::Layer->new( $surface, $pos_x,                           %data );
  my $layer = SDLx::Layer->new( $surface, $pos_x, $pos_y,                   %data );
  my $layer = SDLx::Layer->new( $surface, $pos_x, $pos_y, $clip_w,          %data );
  my $layer = SDLx::Layer->new( $surface, $pos_x, $pos_y, $clip_w, $clip_h, %data );

This constructs the layer object. See how you can omit the position and dimension of the layer. The hash %data is for your use only. The layer object just pass it through.  

index

  my $index = $layer->index;

The method "index" represents the z-index of this layer within its layermanager.  

x

  my $x = $layer->x;

This is a shortcut for $layer->pos->x.  

y

  my $y = $layer->y;

This is a shortcut for $layer->pos->y.  

w

  my $w = $layer->w;

This is a shortcut for $layer->clip->w.  

h

  my $h = $layer->h;

This is a shortcut for $layer->pos->h.  

surface

  my $surface = $layer->surface;
  my $surface = $layer->surface( $new_surface );

Example:

  SDL::Video::blit_surface( $layer->surface, $layer->clip, $destination_surface, $layer->pos );

This method let you retrieve the current or set a new surface.  

pos

  my $rect = $layer->pos;

The method "pos" returns an SDL::Rect object. The pos x and y are stored there.

Example:

  SDL::Video::blit_surface( $layer->surface, $layer->clip, $destination_surface, $layer->pos );

 

clip

  my $rect = $layer->clip;

The method "clip" returns an SDL::Rect object. The clip width and height are stored there.

Example:

  SDL::Video::blit_surface( $layer->surface, $layer->clip, $destination_surface, $layer->pos );

 

data

  my %data = %{ $layer->data };
  my %data = %{ $layer->data( %new_data) };

This method returns the hash %data. You can set %data by passing a hash.  

ahead

  my @layers = $layer->ahead;

This method returns all layers that are ahead of the given layer. 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 = $layer->behind;

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

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

attach

  $layer->attach( $x, $y );

This function makes the given layer sticky to the mouse. If you move the mouse the layer will follow. The layermanager blits this layer 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 layer obtains them via SDL::Events::get_mouse_state.

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

detach_xy

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

"detach_xy" detaches the previously attached layer to the given coords. The upper left corner of this layer will be at $x and $y.  

foreground

  $layer->foreground;

This method moves the given layer to the foreground so that it is blitted on top of the other layers.  

BUGS

Report at sdlperl.ath.cx  

SUPPORT

#sdl irc.perl.org  

AUTHORS

See ``AUTHORS'' in SDL.  

COPYRIGHT

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

The full text of the license can be found in the LICENSE file included with this module.  

SEE ALSO

perl(1), SDL(2).


 

Index

NAME
CATEGORY
SYNOPSIS
DESCRIPTION
METHODS
new
index
x
y
w
h
surface
pos
clip
data
ahead
behind
attach
detach_xy
foreground
BUGS
SUPPORT
AUTHORS
COPYRIGHT
SEE ALSO
LinuxReviews : manual page archive : man3pm