lcd.hpp File Reference

Functions for interacting with the LCD and VRAM. More...

#include <stdint.h>

Include dependency graph for lcd.hpp:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Macros
#define	RGB_TO_RGB565(r, g, b)
#define	RGB565_TO_R(rgb565)   ((rgb565 >> 11) & 0x1F)
#define	RGB565_TO_G(rgb565)   ((rgb565 >> 5) & 0x3F)
#define	RGB565_TO_B(rgb565)   (rgb565 & 0x1F)

Functions
void	LCD_ClearScreen ()
uint16_t	LCD_GetPixel (int x, int y)
void	LCD_GetSize (int *width, int *height)
uint16_t *	LCD_GetVRAMAddress ()
void	LCD_Refresh ()
void	LCD_SetPixel (int x, int y, uint16_t color)
void	LCD_SetPixelFromPalette (int x, int y, uint8_t index)
void	LCD_VRAMBackup ()
void	LCD_VRAMRestore ()

Variables
const uint8_t	PALETTE_BLACK = 0
const uint8_t	PALETTE_BLUE = 1
const uint8_t	PALETTE_GREEN = 2
const uint8_t	PALETTE_CYAN = 3
const uint8_t	PALETTE_RED = 4
const uint8_t	PALETTE_MAGENTA = 5
const uint8_t	PALETTE_YELLOW = 6
const uint8_t	PALETTE_WHITE = 7

Detailed Description

Functions for interacting with the LCD and VRAM.

Different levels of indirection are availiable to write to VRAM (direct memory access, getter/setters and palette-based drawing). The contents of VRAM are not automatically drawn to the LCD, and must be rendered with LCD_Refresh.

Example: drawing a 30x50 rectangle at 10, 20 in purple

uint16_t *vram = LCD_GetVRAMAddress();
int width, height;
LCD_GetSize(&width, &height);
 
for (int y = 0; y < 50; ++y) {
    for (int x = 0; x < 30; ++x) {
        vram[(x + 10) + (y + 20) * width] = RGB_TO_RGB565(0x1F, 0x3B, 0x08);
    }
}
 
// Put our changes on the display
LCD_Refresh();

Macro Definition Documentation

RGB565_TO_B

#define RGB565_TO_B

(

rgb565

)

(rgb565 & 0x1F)

Extracts the blue component from an RGB565 value.

Parameters

rgb565

The RGB565 value.

Returns

The blue component.

RGB565_TO_G

#define RGB565_TO_G

(

rgb565

)

((rgb565 >> 5) & 0x3F)

Extracts the green component from an RGB565 value.

Parameters

rgb565

The RGB565 value.

Returns

The green component.

RGB565_TO_R

#define RGB565_TO_R

(

rgb565

)

((rgb565 >> 11) & 0x1F)

Extracts the red component from an RGB565 value.

Parameters

rgb565

The RGB565 value.

Returns

The red component.

RGB_TO_RGB565

#define RGB_TO_RGB565	(		r,
			g,
			b
	)

Value:

    ( \
    ((r & 0x1F) << 11) | \
    ((g & 0x3F) << 5) | \
    (b & 0x1F) \
)

Converts three RGB values into one RGB565 value.

Parameters

r	The red component, between 0 and 31 (0x1F) inclusive.
g	The green component, between 0 and 63 (0x3F) inclusive.
b	The blue component, between 0 and 31 (0x1F) inclusive.

Returns

The specified color, in RGB565 format.

Function Documentation

LCD_ClearScreen()

void LCD_ClearScreen

(

)

Clears the LCD. Fills VRAM with white, but does not refresh the LCD.

LCD_GetPixel()

uint16_t LCD_GetPixel	(	int	x,
		int	y
	)

Returns the color of a pixel. This is not necessarily the color which is being displayed on the LCD, but instead is the color specified for the pixel in the VRAM buffer. Color is in RGB565 format.

Parameters

x,y	The coordinates of the pixel.

Returns

The color of the pixel, in RGB565 format.

LCD_GetSize()

void LCD_GetSize	(	int *	width,
		int *	height
	)

Retrieves the size, in pixels, of the LCD.

Parameters

[out]

width,height

The LCD's size.

LCD_GetVRAMAddress()

uint16_t * LCD_GetVRAMAddress

(

)

Returns a pointer to the video RAM. Video RAM is composed of width * height 16-bit integers (in row-major order) representing the color at each pixel, in RGB565 format.

Returns

A pointer to the VRAM.

LCD_Refresh()

void LCD_Refresh

(

)

Pushes the content of the VRAM to the LCD.

LCD_SetPixel()

void LCD_SetPixel	(	int	x,
		int	y,
		uint16_t	color
	)

Sets the color of a pixel. The result of this operation will not be visible until LCD_Refresh is called. Color is in RGB565 format.

Parameters

x,y	The coordinate of the pixel.
color	The color to set the pixel, in RGB565 format.

LCD_SetPixelFromPalette()

void LCD_SetPixelFromPalette	(	int	x,
		int	y,
		uint8_t	index
	)

Sets the color of a pixel, from a pre-defined palette. Result is not visible until LCD_Refresh is called. See Palette Colors.

Parameters

x,y	The coordinate of the pixel.
index	The index of the color in the palette to use.

LCD_VRAMBackup()

void LCD_VRAMBackup

(

)

Backs up the current contents of VRAM.

Should be used to prevent display corruption when writing directly to VRAM.

Used in conjunction with LCD_VRAMRestore.

LCD_VRAMRestore()

void LCD_VRAMRestore

(

)

Restores the backed up contents of VRAM. The restored content is not displayed until LCD_Refresh is called.

Used in conjunction with LCD_VRAMBackup.