Fl_Tiled_Image Class Reference

This class supports tiling of images over a specified area. More...

#include <Fl_Tiled_Image.H>

Inheritance diagram for Fl_Tiled_Image:
Fl_Image

List of all members.

Public Member Functions

virtual void color_average (Fl_Color c, float i)
 The color_average() method averages the colors in the image with the FLTK color value c.
Fl_Imagecopy ()
 The copy() method creates a copy of the specified image.
virtual Fl_Imagecopy (int W, int H)
 The copy() method creates a copy of the specified image.
virtual void desaturate ()
 The desaturate() method converts an image to grayscale.
void draw (int X, int Y)
 Draws the image.
virtual void draw (int X, int Y, int W, int H, int cx, int cy)
 Draws a tiled image.
 Fl_Tiled_Image (Fl_Image *i, int W=0, int H=0)
 The constructors create a new tiled image containing the specified image.
Fl_Imageimage ()
 Gets The image that is tiled.
virtual ~Fl_Tiled_Image ()
 The destructor frees all memory and server resources that are used by the tiled image.

Protected Attributes

int alloc_image_
Fl_Imageimage_

Detailed Description

This class supports tiling of images over a specified area.

The source (tile) image is not copied unless you call the color_average(), desaturate(), or inactive() methods.


Constructor & Destructor Documentation

Fl_Tiled_Image::Fl_Tiled_Image ( Fl_Image i,
int  W = 0,
int  H = 0 
)

The constructors create a new tiled image containing the specified image.

Use a width and height of 0 to tile the whole window/widget.

Note:
Due to implementation constraints in FLTK 1.3.3 and later width and height of 0 may not work as expected when used as background image in widgets other than windows. You may need to center and clip the image (label) and set the label type to FL_NORMAL_LABEL. Doing so will let the tiled image fill the whole widget as its background image. Other combinations of label flags may or may not work.
  #include "bg.xpm"
  Fl_Pixmap *bg_xpm = new Fl_Pixmap(bg_xpm);
  Fl_Tiled_Image *bg_tiled = new Fl_Tiled_Image(bg_xpm,0,0);

  Fl_Box *box = new Fl_Box(40,40,300,100,"");
  box->box(FL_UP_BOX);
  box->labeltype(FL_NORMAL_LABEL);
  box->align(FL_ALIGN_INSIDE | FL_ALIGN_CENTER | FL_ALIGN_CLIP);
  box->image(bg_tiled);
Note:
Setting an image (label) for a window may not work as expected due to implementation constraints in FLTK 1.3.x and maybe later. The reason is the way Fl::scheme() initializes the window's label type and image. A possible workaround is to use another Fl_Group as the only child widget and to set the background image for this group as described above.
Todo:
Fix Fl_Tiled_Image as background image for widgets and windows and fix the implementation of Fl::scheme(const char *).

Member Function Documentation

void Fl_Tiled_Image::color_average ( Fl_Color  c,
float  i 
) [virtual]

The color_average() method averages the colors in the image with the FLTK color value c.

The i argument specifies the amount of the original image to combine with the color, so a value of 1.0 results in no color blend, and a value of 0.0 results in a constant image of the specified color.

An internal copy is made of the original image before changes are applied, to avoid modifying the original image.

Reimplemented from Fl_Image.

Fl_Image* Fl_Tiled_Image::copy (  )  [inline]

The copy() method creates a copy of the specified image.

If the width and height are provided, the image is resized to the specified size. The image should be deleted (or in the case of Fl_Shared_Image, released) when you are done with it.

Reimplemented from Fl_Image.

Fl_Image * Fl_Tiled_Image::copy ( int  W,
int  H 
) [virtual]

The copy() method creates a copy of the specified image.

If the width and height are provided, the image is resized to the specified size. The image should be deleted (or in the case of Fl_Shared_Image, released) when you are done with it.

Reimplemented from Fl_Image.

void Fl_Tiled_Image::desaturate (  )  [virtual]

The desaturate() method converts an image to grayscale.

If the image contains an alpha channel (depth = 4), the alpha channel is preserved.

An internal copy is made of the original image before changes are applied, to avoid modifying the original image.

Reimplemented from Fl_Image.

void Fl_Tiled_Image::draw ( int  X,
int  Y 
) [inline]

Draws the image.

This form specifies the upper-lefthand corner of the image.

Reimplemented from Fl_Image.

void Fl_Tiled_Image::draw ( int  X,
int  Y,
int  W,
int  H,
int  cx,
int  cy 
) [virtual]

Draws a tiled image.

Tiled images can be used as background images for widgets and windows. However, due to implementation constraints, you must take care when setting label types and alignment flags. Only certain combinations work as expected, others may yield unexpected results and undefined behavior.

This draw method can draw multiple copies of one image in an area given by X, Y, W, H.

The optional arguments cx and cy can be used to crop the image starting at offsets (cx, cy). cx and cy must be >= 0 (negative values are ignored). If one of the values is greater than the image width or height resp. (cx >= image()->w() or cy >= image()->h()) nothing is drawn, because the resulting image would be empty.

After calculating the resulting image size the image is drawn as often as necessary to fill the given area, starting at the top left corner.

If both W and H are 0 the image is repeated as often as necessary to fill the entire window, unless there is a valid clip region. If you want to fill only one particular widget's background, then you should either set a clip region in your draw() method or use the label alignment flags FL_ALIGN_INSIDE|FL_ALIGN_CLIP to make sure the image is clipped.

This may be improved in a later version of the library.

Reimplemented from Fl_Image.


The documentation for this class was generated from the following files: