FLTK 1.4.0: Fl_RGB_Image Class Reference

The Fl_RGB_Image class supports caching and drawing of full-color images with 1 to 4 channels of color information. More...

#include <Fl_Image.H>

Inheritance diagram for Fl_RGB_Image:

Public Member Functions
virtual Fl_SVG_Image *	as_svg_image ()
	Returns whether an image is an Fl_SVG_Image or not. More...

int	cache_h ()

int	cache_w ()

void	color_average (Fl_Color c, float i) FL_OVERRIDE
	The color_average() method averages the colors in the image with the provided FLTK color value. More...

Fl_Image *	copy () const

Fl_Image *	copy (int W, int H) const FL_OVERRIDE
	Creates a resized copy of the image. More...

void	desaturate () FL_OVERRIDE
	The desaturate() method converts an image to grayscale. More...

void	draw (int X, int Y)

void	draw (int X, int Y, int W, int H, int cx=0, int cy=0) FL_OVERRIDE
	Draws the image to the current drawing surface with a bounding box. More...

	Fl_RGB_Image (const Fl_Pixmap *pxm, Fl_Color bg=FL_GRAY)
	The constructor creates a new RGBA image from the specified Fl_Pixmap. More...

	Fl_RGB_Image (const uchar *bits, int bits_length, int W, int H, int D, int LD)
	The constructor creates a new image from the specified data. More...

	Fl_RGB_Image (const uchar *bits, int W, int H, int D=3, int LD=0)
	The constructor creates a new image from the specified data. More...

void	label (Fl_Menu_Item *m) FL_OVERRIDE
	This method is an obsolete way to set the image attribute of a menu item. More...

void	label (Fl_Widget *w) FL_OVERRIDE
	This method is an obsolete way to set the image attribute of a widget or menu item. More...

virtual void	normalize ()
	Makes sure the object is fully initialized. More...

void	uncache () FL_OVERRIDE
	If the image has been cached for display, delete the cache data. More...

	~Fl_RGB_Image () FL_OVERRIDE
	The destructor frees all memory and server resources that are used by the image.

Public Member Functions inherited from Fl_Image
virtual class Fl_Shared_Image *	as_shared_image ()
	Returns whether an image is an Fl_Shared_Image or not. More...

virtual void	color_average (Fl_Color c, float i)
	The color_average() method averages the colors in the image with the provided FLTK color value. More...

Fl_Image *	copy () const
	Creates a copy of the image in the same size. More...

virtual Fl_Image *	copy (int W, int H) const
	Creates a resized copy of the image. More...

int	count () const
	Returns the number of data values associated with the image. More...

int	d () const
	Returns the image depth. More...

const char const	data () const
	Returns a pointer to the current image data array. More...

int	data_h () const
	Returns the height of the image data.

int	data_w () const
	Returns the width of the image data.

virtual void	desaturate ()
	The desaturate() method converts an image to grayscale. More...

void	draw (int X, int Y)
	Draws the image to the current drawing surface. More...

virtual void	draw (int X, int Y, int W, int H, int cx=0, int cy=0)
	Draws the image to the current drawing surface with a bounding box. More...

int	fail () const
	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 drawing height in FLTK units. More...

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)
	This method is an obsolete way to set the image attribute of a menu item. More...

virtual void	label (Fl_Widget *w)
	This method is 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	release ()
	Releases an Fl_Image - the same as '`delete` `this'`. More...

virtual void	scale (int width, int height, int proportional=1, int can_expand=0)
	Sets the drawing size of the image. More...

virtual void	uncache ()
	If the image has been cached for display, delete the cache data. More...

int	w () const
	Returns the current image drawing width in FLTK units. More...

virtual	~Fl_Image ()
	The destructor is a virtual method that frees all memory used by the image.

Static Public Member Functions
static size_t	max_size ()
	Returns the maximum allowed image size in bytes when creating an Fl_RGB_Image object. More...

static void	max_size (size_t size)
	Sets the maximum allowed image size in bytes when creating an Fl_RGB_Image object. More...

Static Public Member Functions inherited from Fl_Image
static Fl_Labeltype	define_FL_IMAGE_LABEL ()

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 Fl_RGB_Scaling	scaling_algorithm ()
	Gets what algorithm is used when resizing a source image to draw it.

static void	scaling_algorithm (Fl_RGB_Scaling algorithm)
	Sets what algorithm is used when resizing a source image to draw it. More...

Public Attributes
int	alloc_array
	If non-zero, the object's data array is delete[]'d when deleting the object.

const uchar *	array
	Points to the start of the object's data array. More...

Friends
class	Fl_Graphics_Driver

Additional Inherited Members
Static Public Attributes inherited from Fl_Image
static const int	ERR_FILE_ACCESS = -2

static const int	ERR_FORMAT = -3

static const int	ERR_MEMORY_ACCESS = -4

static const int	ERR_NO_IMAGE = -1

static bool	register_images_done = false
	True after fl_register_images() was called, false before.

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 data pointer and count of pointers in the array. More...

void	draw_empty (int X, int Y)
	The protected method draw_empty() draws a box with an X in it. More...

int	draw_scaled (int X, int Y, int W, int H)
	Draw the image to the current drawing surface rescaled to a given width and height. More...

void	h (int H)
	Sets the height of the image data. More...

void	ld (int LD)
	Sets the current line data size in bytes. More...

void	w (int W)
	Sets the width of the image data. More...

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

The Fl_RGB_Image class supports caching and drawing of full-color images with 1 to 4 channels of color information.

Images with an even number of channels are assumed to contain alpha information, which is used to blend the image with the contents of the screen.

Fl_RGB_Image is defined in <FL/Fl_Image.H>, however for compatibility reasons <FL/Fl_RGB_Image.H> should be included.

Constructor & Destructor Documentation

◆ Fl_RGB_Image() [1/3]

Fl_RGB_Image::Fl_RGB_Image	(	const uchar *	bits,
		int	W,
		int	H,
		int	D = `3`,
		int	LD = `0`
	)

The constructor creates a new image from the specified data.

The data array bits must contain sufficient data to provide W * H * D image bytes and optional line padding, see LD.

W and H are the width and height of the image in pixels, resp.

D is the image depth and can be:

D=1: each uchar in bits[] is a grayscale pixel value
D=2: each uchar pair in bits[] is a grayscale + alpha pixel value
D=3: each uchar triplet in bits[] is an R/G/B pixel value
D=4: each uchar quad in bits[] is an R/G/B/A pixel value

LD specifies the line data size of the array, see Fl_Image::ld(int). If LD is zero, then W * D is assumed, otherwise LD must be greater than or equal to W * D to account for (unused) extra data per line (padding).

The caller is responsible that the image data array bits persists as long as the image is used.

This constructor sets Fl_RGB_Image::alloc_array to 0. To have the image object control the deallocation of the data array bits, set alloc_array to non-zero after construction.

Parameters

[in]	bits	The image data array.
[in]	W	The width of the image in pixels.
[in]	H	The height of the image in pixels.
[in]	D	The image depth, or 'number of channels' (default=3).
[in]	LD	Line data size (default=0).

See also: Fl_Image::data(), Fl_Image::w(), Fl_Image::h(), Fl_Image::d(), Fl_Image::ld(int)

◆ Fl_RGB_Image() [2/3]

Fl_RGB_Image::Fl_RGB_Image	(	const uchar *	bits,
		int	bits_length,
		int	W,
		int	H,
		int	D,
		int	LD
	)

The constructor creates a new image from the specified data.

If the provided array is too small to contain all the image data, the constructor will not generate the image to avoid illegal memory read access and instead set data to NULL and ld to ERR_MEMORY_ACCESS.

Parameters

bits	image data
bits_length	length of the `bits` array in bytes
W	image width in pixels
H	image height in pixels
D	image depth in bytes, 1 for gray scale, 2 for gray with alpha, 3 for RGB, and 4 for RGB plus alpha
LD	line length in bytes, or 0 to use W*D.

See also: Fl_RGB_Image(const uchar *bits, int W, int H, int D, int LD)

◆ Fl_RGB_Image() [3/3]

Fl_RGB_Image::Fl_RGB_Image	(	const Fl_Pixmap *	pxm,
		Fl_Color	bg = `FL_GRAY`
	)

The constructor creates a new RGBA image from the specified Fl_Pixmap.

The RGBA image is built fully opaque except for the transparent area of the pixmap that is assigned the bg color with full transparency.

This constructor creates a new internal data array and sets Fl_RGB_Image::alloc_array to 1 so the data array is deleted when the image is destroyed.

Member Function Documentation

◆ as_svg_image()

virtual Fl_SVG_Image * Fl_RGB_Image::as_svg_image ( )

inlinevirtual

Returns whether an image is an Fl_SVG_Image or not.

This virtual method returns a pointer to the Fl_SVG_Image if this object is an instance of Fl_SVG_Image or NULL if not.

Reimplemented in Fl_SVG_Image.

◆ color_average()

void Fl_RGB_Image::color_average	(	Fl_Color	c,
		float	i
	)

virtual

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

The first argument specifies the FLTK color to be used.

The second 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 data before changes are applied, to avoid modifying the original image data in memory.

Reimplemented from Fl_Image.

Reimplemented in Fl_SVG_Image.

◆ copy()

Fl_Image * Fl_RGB_Image::copy	(	int	W,
		int	H
	)		const

virtual

Creates a resized copy of the image.

It is recommended not to call this member function to reduce the size of an image to the size of the area where this image will be drawn, and to use Fl_Image::scale() instead.

The new image should be released when you are done with it.

Note: since FLTK 1.4.0 you can use Fl_Image::release() for all types of images (i.e. all subclasses of Fl_Image) instead of operator delete for Fl_Image's and Fl_Image::release() for Fl_Shared_Image's.

The new image data will be converted to the requested size. RGB images are resized using the algorithm set by Fl_Image::RGB_scaling().

For the new image the following equations are true:

w() == data_w() == W
h() == data_h() == H

Parameters

[in] W,H Requested width and height of the new image

Note: The returned image can be safely cast to the same image type as that of the source image provided this type is one of Fl_RGB_Image, Fl_SVG_Image, Fl_Pixmap, Fl_Bitmap, Fl_Tiled_Image, Fl_Anim_GIF_Image and Fl_Shared_Image. Returned objects copied from images of other, derived, image classes belong to the parent class appearing in this list. For example, the copy of an Fl_GIF_Image is an object of class Fl_Pixmap.; Since FLTK 1.4.0 this method is 'const'. If you derive your own class from Fl_Image or any subclass your overridden methods of 'Fl_Image::copy() const' and 'Fl_Image::copy(int, int) const' must also be 'const' for inheritance to work properly. This is different than in FLTK 1.3.x and earlier where these methods have not been 'const'.

Reimplemented from Fl_Image.

Reimplemented in Fl_SVG_Image.

◆ desaturate()

void Fl_RGB_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 data before changes are applied, to avoid modifying the original image data in memory.

Reimplemented from Fl_Image.

Reimplemented in Fl_SVG_Image.

◆ draw()

void Fl_RGB_Image::draw	(	int	X,
		int	Y,
		int	W,
		int	H,
		int	cx = `0`,
		int	cy = `0`
	)

virtual

Draws the image to the current drawing surface with a bounding box.

Arguments X,Y,W,H specify a bounding box for the image, with the origin (upper-left corner) of the image offset by the cx and cy arguments.

In other words: fl_push_clip(X,Y,W,H) is applied, the image is drawn with its upper-left corner at X-cx,Y-cy and its own width and height, fl_pop_clip() is applied.

Reimplemented from Fl_Image.

Reimplemented in Fl_SVG_Image.

◆ label() [1/2]

void Fl_RGB_Image::label ( Fl_Menu_Item * m )

virtual

This method is an obsolete way to set the image attribute of a menu item.

Deprecated:: Please use Fl_Menu_Item::image() instead.

Reimplemented from Fl_Image.

◆ label() [2/2]

void Fl_RGB_Image::label ( Fl_Widget * widget )

virtual

This method is an obsolete way to set the image attribute of a widget or menu item.

Deprecated:: Please use Fl_Widget::image() or Fl_Widget::deimage() instead.

Reimplemented from Fl_Image.

◆ max_size() [1/2]

static size_t Fl_RGB_Image::max_size ( )

inlinestatic

Returns the maximum allowed image size in bytes when creating an Fl_RGB_Image object.

See also: void Fl_RGB_Image::max_size(size_t)

◆ max_size() [2/2]

static void Fl_RGB_Image::max_size ( size_t size )

inlinestatic

Sets the maximum allowed image size in bytes when creating an Fl_RGB_Image object.

The image size in bytes of an Fl_RGB_Image object is the value of the product w() * h() * d(). If this product exceeds size, the created object of a derived class of Fl_RGB_Image won't be loaded with the image data. This does not apply to direct RGB image creation with Fl_RGB_Image::Fl_RGB_Image(const uchar *bits, int W, int H, int D, int LD). The default max_size() value is essentially infinite.

◆ normalize()

virtual void Fl_RGB_Image::normalize ( )

inlinevirtual

Makes sure the object is fully initialized.

In particular, makes sure member variable array is non-null.

Reimplemented in Fl_SVG_Image.

◆ uncache()

void Fl_RGB_Image::uncache ( )

virtual

If the image has been cached for display, delete the cache data.

This allows you to change the data used for the image and then redraw it without recreating an image object.

Reimplemented from Fl_Image.

Member Data Documentation

◆ array

const uchar* Fl_RGB_Image::array

Points to the start of the object's data array.

See also: class Fl_SVG_Image which delays initialization of this member variable.

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

Fl_Image.H
Fl_Image.cxx

Public Member Functions

Static Public Member Functions

Public Attributes

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Fl_RGB_Image() [1/3]

◆ Fl_RGB_Image() [2/3]

◆ Fl_RGB_Image() [3/3]

Member Function Documentation

◆ as_svg_image()

◆ color_average()

◆ copy()

◆ desaturate()

◆ draw()

◆ label() [1/2]

◆ label() [2/2]

◆ max_size() [1/2]

◆ max_size() [2/2]

◆ normalize()

◆ uncache()

Member Data Documentation

◆ array