Fl_Image_Surface Class Reference

Directs all graphics requests to an Fl_Image. More...

#include <Fl_Image_Surface.H>

Inheritance diagram for Fl_Image_Surface:

Public Member Functions
const char *	class_name ()
	Returns the name of the class of this object. More...
void	draw (Fl_Widget *, int delta_x=0, int delta_y=0)
	Draws a widget in the image surface. More...
void	draw_decorated_window (Fl_Window *win, int delta_x=0, int delta_y=0)
	Draws a window and its borders and title bar to the image drawing surface. More...
	Fl_Image_Surface (int w, int h, int highres=0)
	Constructor with optional high resolution. More...
Fl_Shared_Image *	highres_image ()
	Returns a possibly high resolution image made of all drawings sent to the Fl_Image_Surface object. More...
Fl_RGB_Image *	image ()
	Returns an image made of all drawings sent to the Fl_Image_Surface object. More...
void	set_current ()
	Make this surface the current drawing surface. More...
	~Fl_Image_Surface ()
	The destructor.
Public Member Functions inherited from Fl_Surface_Device
const char *	class_name ()
	Returns the name of the class of this object. More...
Fl_Graphics_Driver *	driver ()
	Returns the graphics driver of this drawing surface.
void	driver (Fl_Graphics_Driver *graphics_driver)
	Sets the graphics driver of this drawing surface.
virtual void	set_current (void)
	Make this surface the current drawing surface. More...
virtual	~Fl_Surface_Device ()
	The destructor.
Public Member Functions inherited from Fl_Device
virtual const char *	class_name ()
	Returns the name of the class of this object. More...
virtual	~Fl_Device ()
	Virtual destructor. More...

Static Public Attributes
static const char *	class_id = "Fl_Image_Surface"
Static Public Attributes inherited from Fl_Surface_Device
static const char *	class_id = "Fl_Surface_Device"
Static Public Attributes inherited from Fl_Device
static const char *	class_id = "Fl_Device"
	A string that identifies each subclass of Fl_Device. More...

Additional Inherited Members
Static Public Member Functions inherited from Fl_Surface_Device
static Fl_Surface_Device *	surface ()
	The current drawing surface. More...
Protected Member Functions inherited from Fl_Surface_Device
	Fl_Surface_Device (Fl_Graphics_Driver *graphics_driver)
	Constructor that sets the graphics driver to use for the created surface.

Detailed Description

Directs all graphics requests to an Fl_Image.

After creation of an Fl_Image_Surface object, call set_current() on it, and all subsequent graphics requests will be recorded in the image. It's possible to draw widgets (using Fl_Image_Surface::draw()) or to use any of the Drawing functions or the Color & Font functions. Finally, call image() on the object to obtain a newly allocated Fl_RGB_Image object.
Fl_GL_Window objects can be drawn in the image as well.

Usage example:

Fl_Widget *g = ...; // a widget you want to draw in an image
Fl_Image_Surface *img_surf = new Fl_Image_Surface(g->w(), g->h()); // create an Fl_Image_Surface object
img_surf->set_current(); // direct graphics requests to the image
fl_color(FL_WHITE); fl_rectf(0, 0, g->w(), g->h()); // draw a white background
img_surf->draw(g); // draw the g widget in the image
Fl_RGB_Image* image = img_surf->image(); // get the resulting image
delete img_surf; // delete the img_surf object
Fl_Display_Device::display_device()->set_current();  // direct graphics requests back to the display

Constructor & Destructor Documentation

Fl_Image_Surface()

Fl_Image_Surface::Fl_Image_Surface	(	int	w,
		int	h,
		int	highres = 0
	)

Constructor with optional high resolution.

Parameters

w	and
h	give the size in pixels of the resulting image.
highres	if non-zero, the surface pixel size is twice as high and wide as w and h, which is useful to draw it later on a high resolution display (e.g., retina display). This is implemented for the Mac OS platform only. If highres is non-zero, use Fl_Image_Surface::highres_image() to get the image data.

Version

1.3.4 and requires compilation with -DFL_ABI_VERSION=10304 (1.3.3 without the highres parameter)

Member Function Documentation

class_name()

const char * Fl_Image_Surface::class_name ( )

inlinevirtual

Returns the name of the class of this object.

Use of the class_name() function is discouraged because it will be removed from future FLTK versions.

The class of an instance of an Fl_Device subclass can be checked with code such as:

if ( instance->class_name() == Fl_Printer::class_id ) { ... }

Reimplemented from Fl_Surface_Device.

draw()

void Fl_Image_Surface::draw	(	Fl_Widget *	widget,
		int	delta_x = 0,
		int	delta_y = 0
	)

Draws a widget in the image surface.

Parameters

widget	any FLTK widget (e.g., standard, custom, window, GL view) to draw in the image
delta_x	and
delta_y	give the position in the image of the top-left corner of the widget

draw_decorated_window()

void Fl_Image_Surface::draw_decorated_window	(	Fl_Window *	win,
		int	delta_x = 0,
		int	delta_y = 0
	)

Draws a window and its borders and title bar to the image drawing surface.

Parameters

win	an FLTK window to draw in the image
delta_x	and
delta_y	give the position in the image of the top-left corner of the window's title bar

highres_image()

Fl_Shared_Image * Fl_Image_Surface::highres_image

(

)

Returns a possibly high resolution image made of all drawings sent to the Fl_Image_Surface object.

The Fl_Image_Surface object should have been constructed with Fl_Image_Surface(W, H, 1). The returned image is scaled to a size of WxH drawing units and may have a pixel size twice as wide and high. The returned object should be deallocated with Fl_Shared_Image::release() after use.

Version

1.3.4 and requires compilation with -DFL_ABI_VERSION=10304

image()

Fl_RGB_Image * Fl_Image_Surface::image

(

)

Returns an image made of all drawings sent to the Fl_Image_Surface object.

The returned object contains its own copy of the RGB data. Prefer Fl_Image_Surface::highres_image() if the surface was constructed with the highres option on.

set_current()

void Fl_Image_Surface::set_current ( void  )

virtual

Make this surface the current drawing surface.

This surface will receive all future graphics requests.

Reimplemented from Fl_Surface_Device.

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

• Fl_Image_Surface.H
• Fl_Image_Surface.cxx