Driver managing the video mode and synchronizing its buffer with the graphics printer. More...

#include <device/graphics.h>

Inheritance diagram for Graphics:

Public Member Functions
	Graphics (unsigned size, void frontbuffer, void backbuffer)
	Constructor. More...

bool	init (bool force=false)
	Initialize GraphicsPrinter according to the current video mode. More...

bool	switchBuffers ()
	Switch front and back buffer (only if front buffer was already copied to video memory) More...

void	scanoutFrontbuffer ()
	Copy current front buffer to the video memory.

void	clear ()
	Clear all pixel of the current back buffer (set full screen to black)

bool	valid (const Point &p)
	Check if a Point can be displayed at the current resolution. More...

unsigned	height ()
	Number of vertical pixels in current resolution. More...

unsigned	width ()
	Number of horizontal pixels in current resolution. More...

void	pixel (const Point &p, const Color &color)
	Draw a pixel on the current back buffer. More...

void	pixel (const Point &p, const ColorAlpha &color)
	Draw a pixel on the current back buffer. More...

void	line (const Point &start, const Point &end, const Color &color)
	Draw a line on the current back buffer. More...

void	line (const Point &start, const Point &end, const ColorAlpha &color)
	Draw a line on the current back buffer. More...

void	rectangle (const Point &start, const Point &end, const Color &color, bool filled=true)
	Draw a rectangle on the current back buffer. More...

void	rectangle (const Point &start, const Point &end, const ColorAlpha &color, bool filled=true)
	Draw a rectangle on the current back buffer. More...

void	font (const Font &new_font)
	Change the current font for text output in video mode. More...

void	text (const Point &p, const char string, unsigned len, const Color &color, const Font font=nullptr)
	Print text (without automatic word wrap) on the current back buffer. More...

void	text (const Point &p, const char string, unsigned len, const ColorAlpha &color, const Font font=nullptr)
	Print text (without automatic word wrap) on the current back buffer. More...

void	image (const Point &p, PNG &image, unsigned width=0, unsigned height=0, unsigned offset_x=0, unsigned offset_y=0)
	Draw a PNG image [detail] on the current back buffer. More...

void	image (const Point &p, const GIMP &image, unsigned width=0, unsigned height=0, unsigned offset_x=0, unsigned offset_y=0)
	Draw a GIMP image [detail] on the current back buffer. More...

void	image (const Point &p, const Color *image, unsigned width, unsigned height, unsigned offset_x=0, unsigned offset_y=0)
	Draw a sprite on the current back buffer. More...

void	image (const Point &p, const ColorAlpha *image, unsigned width, unsigned height, unsigned offset_x=0, unsigned offset_y=0)
	Draw a sprite with alpha blending (transparency) on the current back buffer. More...

Detailed Description

Driver managing the video mode and synchronizing its buffer with the graphics printer.

This device detects the current video mode set by the Multiboot compliant boot loader and initializes a suitable GraphicsPrinter.

With the methods Graphics::switchBuffers() (to exchange front- and backbuffer) and Graphics::scanoutFrontbuffer() (copying the contents of the frontbuffer into the video memory) it provides some kind of manually triple buffering.

A typical usage is to fully prepare the back buffer before switching it with the front buffer

graphics.init();
while(true) {
    // Draw on back buffer
    // using the primitives provided by the driver
 
    graphics.switchBuffers();
}

The method Graphics::scanoutFrontbuffer() has to be executed either inside the loop (right after Graphics::switchBuffers() in the example above) or at a predefined interval by employing the Watch.

Note: The driver requires Multiboot to initialize a video mode, which can be configured using the flags in boot/multiboot/config.inc.

Constructor & Destructor Documentation

Graphics::Graphics	(	unsigned	size,
		void *	frontbuffer,
		void *	backbuffer
	)

Constructor.

Parameters

size	Size of each buffer
frontbuffer	Pointer to a reserved memory area with a sufficient size to transmit a full screen picture to the video memory at the current video mode / resolution.
backbuffer	Pointer to a reserved memory area with the same size as the front buffer to prepare the picture.

Member Function Documentation

bool Graphics::init ( bool force = false )

Initialize GraphicsPrinter according to the current video mode.

Parameters

force Do not check video attributes for the linear frame buffer (required on our test systems due to some strange VBE behaviour)

Returns: 'true' if a suitable GraphicsPrinter was found for the video mode

bool Graphics::switchBuffers ( )

Switch front and back buffer (only if front buffer was already copied to video memory)

Returns: true if buffers have been switched, false if previous front buffer wasn't yet fully copied to video memory.

bool Graphics::valid ( const Point & p )

inline

Check if a Point can be displayed at the current resolution.

Parameters

p	Coordinates to check

Returns: 'true' if can be displayed

unsigned Graphics::height ( )

inline

Number of vertical pixels in current resolution.

Returns: Height of the screen in current video mode

unsigned Graphics::width ( )

inline

Number of horizontal pixels in current resolution.

Returns: Width of the screen in current video mode

void Graphics::pixel	(	const Point &	p,
		const Color &	color
	)

inline

Draw a pixel on the current back buffer.

Parameters

p	Coordinates of the pixel
color	Color of the pixel

void Graphics::pixel	(	const Point &	p,
		const ColorAlpha &	color
	)

inline

Draw a pixel on the current back buffer.

Parameters

p	Coordinates of the pixel
color	Color of the pixel

void Graphics::line	(	const Point &	start,
		const Point &	end,
		const Color &	color
	)

inline

Draw a line on the current back buffer.

Parameters

start	Coordinates of the begin of the line
end	Coordinates of the end of the line
color	Color of the line

void Graphics::line	(	const Point &	start,
		const Point &	end,
		const ColorAlpha &	color
	)

inline

Draw a line on the current back buffer.

Parameters

start	Coordinates of the begin of the line
end	Coordinates of the end of the line
color	Color of the line

void Graphics::rectangle	(	const Point &	start,
		const Point &	end,
		const Color &	color,
		bool	filled = `true`
	)

inline

Draw a rectangle on the current back buffer.

Parameters

start	Coordinate of the rectangles upper left corner
end	Coordinate of the rectangles lower right corner
color	Color of the rectangle
filled	If set, the rectangle will be filled with the same color. (otherwise only borders will be drawn)

void Graphics::rectangle	(	const Point &	start,
		const Point &	end,
		const ColorAlpha &	color,
		bool	filled = `true`
	)

inline

Draw a rectangle on the current back buffer.

Parameters

start	Coordinate of the rectangles upper left corner
end	Coordinate of the rectangles lower right corner
color	Color of the rectangle
filled	If set, the rectangle will be filled with the same color. (otherwise only borders will be drawn)

void Graphics::font ( const Font & new_font )

inline

Change the current font for text output in video mode.

Parameters

new_font Font to be used on subsequent calls to text (without explicit font parameter)

void Graphics::text	(	const Point &	p,
		const char *	string,
		unsigned	len,
		const Color &	color,
		const Font *	font = `nullptr`
	)

inline

Print text (without automatic word wrap) on the current back buffer.

Parameters

p	Upper left start position of the text
string	Pointer to char array containing the text to be displayed
len	Number of characters to be displayed
color	Color for the text characters
font	Explicit font – or `nullptr` to use default font (set by font method)

void Graphics::text	(	const Point &	p,
		const char *	string,
		unsigned	len,
		const ColorAlpha &	color,
		const Font *	font = `nullptr`
	)

inline

Print text (without automatic word wrap) on the current back buffer.

Parameters

p	Upper left start position of the text
string	Pointer to char array containing the text to be displayed
len	Number of characters to be displayed
color	Color for the text characters
font	Explicit font – or `nullptr` to use default font (set by font method)

void Graphics::image	(	const Point &	p,
		PNG &	image,
		unsigned	width = `0`,
		unsigned	height = `0`,
		unsigned	offset_x = `0`,
		unsigned	offset_y = `0`
	)

inline

Draw a PNG image [detail] on the current back buffer.

The image can has to be in a supported PNG format. Alpha blending (transparency) is supported.

Parameters

p	Coordinate of the images upper left corner
image	Source image to display
width	Width of the image detail (full image width of the source image if zero/default value)
height	Height of the image detail (full image height of the source if zero/default value)
offset_x	Right offset of the source image
offset_y	Top offset of the source image

void Graphics::image	(	const Point &	p,
		const GIMP &	image,
		unsigned	width = `0`,
		unsigned	height = `0`,
		unsigned	offset_x = `0`,
		unsigned	offset_y = `0`
	)

inline

Draw a GIMP image [detail] on the current back buffer.

The image has to be exported as C-source (without Glib types!) in GIMP, alpha blending (transparency) is supported.

Parameters

p	Coordinate of the images upper left corner
image	Source image to display
width	Width of the image detail (full image width of the source image if zero/default value)
height	Height of the image detail (full image height of the source if zero/default value)
offset_x	Right offset of the source image
offset_y	Top offset of the source image

void Graphics::image	(	const Point &	p,
		const Color *	image,
		unsigned	width,
		unsigned	height,
		unsigned	offset_x = `0`,
		unsigned	offset_y = `0`
	)

inline

Draw a sprite on the current back buffer.

Each element in the source array will be displayed as a single pixel.

Parameters

p	Coordinate of the sprites upper left corner
image	Source sprite to display
width	Width of the sprite detail
height	Height of the sprite detail
offset_x	Right offset of the source sprite
offset_y	Top offset of the source sprite

void Graphics::image	(	const Point &	p,
		const ColorAlpha *	image,
		unsigned	width,
		unsigned	height,
		unsigned	offset_x = `0`,
		unsigned	offset_y = `0`
	)

inline

Draw a sprite with alpha blending (transparency) on the current back buffer.

Each element in the source array will be displayed as a single pixel.

Parameters

p	Coordinate of the sprites upper left corner
image	Source sprite to display
width	Width of the sprite detail
height	Height of the sprite detail
offset_x	Right offset of the source sprite
offset_y	Top offset of the source sprite

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

device/graphics.h
device/graphics.cc

Aufgabe 7: Anwendung

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation