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:

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. More...
Fl_Image *	copy ()
virtual Fl_Image *	copy (int W, int H)
	The copy() method creates a copy of the specified image. More...
virtual void	desaturate ()
	The desaturate() method converts an image to grayscale. More...
void	draw (int X, int Y)
virtual void	draw (int X, int Y, int W, int H, int cx, int cy)
	Draws a tiled image. More...
	Fl_Tiled_Image (Fl_Image *i, int W=0, int H=0)
	The constructors create a new tiled image containing the specified image. More...
Fl_Image *	image ()
	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.
Public Member Functions inherited from Fl_Image
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. More...
Fl_Image *	copy ()
	The copy() method creates a copy of the specified image. More...
virtual Fl_Image *	copy (int W, int H)
	The copy() method creates a copy of the specified image. More...
int	count () const
	The count() method returns the number of data values associated with the image. More...
int	d () const
	Returns the current image depth. More...
const char *const *	data () const
	Returns a pointer to the current image data array. More...
virtual void	desaturate ()
	The desaturate() method converts an image to grayscale. More...
void	draw (int X, int Y)
	Draws the image. More...
virtual void	draw (int X, int Y, int W, int H, int cx=0, int cy=0)
	Draws the image with a bounding box. More...
int	fail ()
	Returns a value that is not 0 if there is currently no image available. More...
	Fl_Image (int W, int H, int D)
	The constructor creates an empty image with the specified width, height, and depth. More...
int	h () const
	Returns the current image height in pixels.
void	inactive ()
	The inactive() method calls color_average(FL_BACKGROUND_COLOR, 0.33f) to produce an image that appears grayed out. More...
virtual void	label (Fl_Menu_Item *m)
	The label() methods are an obsolete way to set the image attribute of a widget or menu item. More...
virtual void	label (Fl_Widget *w)
	The label() methods are an obsolete way to set the image attribute of a widget or menu item. More...
int	ld () const
	Returns the current line data size in bytes. More...
virtual void	uncache ()
	If the image has been cached for display, delete the cache data. More...
int	w () const
	Returns the current image width in pixels.
virtual	~Fl_Image ()
	The destructor is a virtual method that frees all memory used by the image.

Protected Attributes
int	alloc_image_
Fl_Image *	image_

Additional Inherited Members
Static Public Member Functions inherited from Fl_Image
static Fl_RGB_Scaling	RGB_scaling ()
	Returns the currently used RGB image scaling method.
static void	RGB_scaling (Fl_RGB_Scaling)
	Sets the RGB image scaling method used for copy(int, int). More...
Static Public Attributes inherited from Fl_Image
static const int	ERR_FILE_ACCESS = -2
static const int	ERR_FORMAT = -3
static const int	ERR_NO_IMAGE = -1
Protected Member Functions inherited from Fl_Image
void	d (int D)
	Sets the current image depth.
void	data (const char *const *p, int c)
	Sets the current array pointer and count of pointers in the array.
void	draw_empty (int X, int Y)
	The protected method draw_empty() draws a box with an X in it. More...
void	h (int H)
	Sets the current image height in pixels.
void	ld (int LD)
	Sets the current line data size in bytes. More...
void	w (int W)
	Sets the current image width in pixels.
Static Protected Member Functions inherited from Fl_Image
static void	labeltype (const Fl_Label *lo, int lx, int ly, int lw, int lh, Fl_Align la)
static void	measure (const Fl_Label *lo, int &lw, int &lh)

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_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

color_average()

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.

copy()

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.

desaturate()

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.

draw()

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:

• Fl_Tiled_Image.H
• Fl_Tiled_Image.cxx