OpenGL utility to render a vil_image_view. More...

#include <vgui_vil_image_renderer.h>

Public Member Functions
	vgui_vil_image_renderer ()
	Constructor - create an empty image renderer.
	~vgui_vil_image_renderer ()
	Destructor - delete image buffer.
void	set_image_resource (vil_image_resource_sptr const &)
	Attach the renderer to a new view.
vil_image_resource_sptr	get_image_resource () const
	Return the image resource that this renderer draws.
void	reread_image ()
	Tell the renderer that the underlying image data has been changed.
void	render (vgui_range_map_params_sptr const &mp)
	Renders the image pixels. If mp not null then render over an interval.
Private Member Functions
bool	old_range_map_params (vgui_range_map_params_sptr const &rmp)
	Are the range params those used to form the current buffer.
bool	render_directly (vgui_range_map_params_sptr const &mp)
	Render the pixels in hardware using the glPixelMap with range_map data.
void	create_buffer (vgui_range_map_params_sptr const &rmp)
	Create a buffer if necessary.
void	create_buffer (vgui_range_map_params_sptr const &rmp, unsigned x0, unsigned y0, unsigned x1, unsigned y1, float zoomx, float zoomy)
	Create a buffer with viewport dimensions.
void	create_buffer (vgui_range_map_params_sptr const &rmp, float zoomx, float zoomy, vil_image_resource_sptr const &ir)
	Create a buffer from specified resource corresponding to a pyramid zoom level.
void	draw_pixels ()
	draw the pixels to the frame buffer.
Private Attributes
vil_image_resource_sptr	the_image_
	Stores the image data (pixels, dimensions, etc).
vgui_section_buffer *	buffer_
	Stored the GL pixels corresponding to the image data.
vgui_range_map_params_sptr	buffer_params_
	a cache for the range map params associated with buffer.
bool	valid_buffer_
	buffer state variable.
vil_memory_chunk_sptr	vbuf_
	a cache when rendering using the gl hardware map.
unsigned	x0_
unsigned	y0_
unsigned	w_
unsigned	h_
float	zx_
float	zy_
unsigned	sni_
unsigned	snj_

Detailed Description

OpenGL utility to render a vil_image_view.

This is not a tableau.

The vil_image_renderer provides an easy way to render sections of an image. It should manage possibly sub-sampled buffers internally to provide a reasonable trade-off between memory consumption and rendering speed. For a very large image, which cannot be stored in core, locally panning the image should not be too slow because sections can be cached at various levels of resolution.

It is assumed that the image is located on the plane z=0 and that image pixel indices i,j (i is the column index, j the row index) describe the x,y-locations of the rendered pixels. It is currently undefined where the centre of a pixel is placed.

Note that the class keeps a vil_image_resource (as given) The image is rendered by extracting appropriate views from the resource There are different modes of rendering based on flags set on the vgui_range_map_params range mapping class. The states are:

1) rmp == null - a buffer is created for the entire image and the buffer supplies glPixels to the display. Range map tables are used where appropriate. No pyramid image support

2) rmp->use_glPixelMap && rmp->cache_mapped_pix pyramid images are handled properly and the range maps are used to generate the scaled pyramid view buffer. gl hardware maps are not used. gl pixels are generated in software using the maps. Rendering is limited to the current viewport. The buffer is updated only if the viewport changes

3) rmp->use_glPixelMap && !rmp->cache_mapped_pix pyramid images are handled properly and the range maps are loaded into gl hardware for rendering. The pyramid image data that drives the hardware is cached as a memory_chunk, but not a pre-mapped glPixel buffer as in 2). The memory_chunk is only updated if the viewport changes.

Definition at line 59 of file vgui_vil_image_renderer.h.

Constructor & Destructor Documentation

vgui_vil_image_renderer::vgui_vil_image_renderer ( )

Constructor - create an empty image renderer.

Definition at line 33 of file vgui_vil_image_renderer.cxx.

vgui_vil_image_renderer::~vgui_vil_image_renderer ( )

Destructor - delete image buffer.

Definition at line 41 of file vgui_vil_image_renderer.cxx.

Member Function Documentation

void vgui_vil_image_renderer::create_buffer ( vgui_range_map_params_sptr const & rmp ) [private]

Create a buffer if necessary.

Definition at line 79 of file vgui_vil_image_renderer.cxx.

void vgui_vil_image_renderer::create_buffer	(	vgui_range_map_params_sptr const &	rmp,
		unsigned	x0,
		unsigned	y0,
		unsigned	x1,
		unsigned	y1,
		float	zoomx,
		float	zoomy
	)		`[private]`

Create a buffer with viewport dimensions.

creates a buffer for a portion of the image.

Definition at line 108 of file vgui_vil_image_renderer.cxx.

void vgui_vil_image_renderer::create_buffer	(	vgui_range_map_params_sptr const &	rmp,
		float	zoomx,
		float	zoomy,
		vil_image_resource_sptr const &	ir
	)		`[private]`