wsg.h File Reference

Detailed Description

Design Philosophy

WSG is a simple image format developed for Swadge sprites. Each pixel in a WSG is from the web-safe palette of colors, with one extra value indicating transparent (paletteColor_t). The pixels are then compressed with heatshrink compression.

WSGs are handled individually, not in a sheet. The assets_preprocessor program will take PNG files and convert them to WSG. The cmake build will take the generated WSG files and generate cnfs_image.c which is included in the firmware Swadge. See assets_preprocessor in CMakeLists.txt.

WSG files can be loaded from the filesystem with helper functions in fs_wsg.h. Once loaded from the filesystem WSGs can be drawn to the display.

Usage

There are five ways to draw a WSG to the display each with varying complexity and speed

• drawWsg(): Draw a WSG to the display with transparency, rotation, and flipping over horizontal or vertical axes. This is the slowest option.
• drawWsgSimple(): Draw a WSG to the display with transparency. This is the medium speed option and should be used if the WSG is not rotated or flipped.
• drawWsgTile(): Draw a WSG to the display without transparency. Any transparent pixels will be an indeterminate color. This is the fastest option, and best for background tiles or images.
• drawWsgSimpleScaled(): Draw a WSG to the display with transparency at a specified scale. Scales are integer values, so 2x, 3x, 4x... are the valid options.
• drawWsgSimpleHalf(): Draw a WSG to the display with transparency at half the original resolution.

Example

// Declare and load an image
wsg_t king_donut;
loadWsg("kid0.wsg", &king_donut, true);
 
// Draw the image to the display
drawWsg(&king_donut, 100, 100, false, false, 0);
 
// Free the image
freeWsg(&king_donut);

Go to the source code of this file.

Data Structures
struct	wsg_t
	A sprite using paletteColor_t colors that can be drawn to the display. More...

Functions
void	rotatePixel (int32_t *x, int32_t *y, int32_t rotateDeg, int32_t width, int32_t height)
void	drawWsg (const wsg_t *wsg, int32_t xOff, int32_t yOff, bool flipLR, bool flipUD, int32_t rotateDeg)
	Draw a WSG to the display.
void	drawWsgSimple (const wsg_t *wsg, int16_t xOff, int16_t yOff)
	Draw a WSG to the display without flipping or rotation.
void	drawWsgSimpleScaled (const wsg_t *wsg, int16_t xOff, int16_t yOff, int16_t xScale, int16_t yScale)
	Draw a WSG to the display without flipping or rotation.
void	drawWsgTile (const wsg_t *wsg, int32_t xOff, int32_t yOff)
	Quickly copy a WSG to the display without flipping or rotation or transparency.
void	drawWsgSimpleHalf (const wsg_t *wsg, int16_t xOff, int16_t yOff)
	Draw a WSG to the display without flipping or rotation at half size.

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Data Structure Documentation

wsg_t

struct wsg_t

Data Fields
paletteColor_t *	px	The row-order array of pixels in the image.
uint16_t	w	The width of the image.
uint16_t	h	The height of the image.

Function Documentation

rotatePixel()

void rotatePixel	(	int32_t *	x,
		int32_t *	y,
		int32_t	rotateDeg,
		int32_t	width,
		int32_t	height )

Transform a pixel's coordinates by rotation around the sprite's center point, then reflection over Y axis, then reflection over X axis, then translation

Parameters

x	The x coordinate of the pixel location to transform
y	The y coordinate of the pixel location to transform
rotateDeg	The number of degrees to rotate clockwise, must be 0-359
width	The width of the image
height	The height of the image

drawWsg()

void drawWsg	(	const wsg_t *	wsg,
		int32_t	xOff,
		int32_t	yOff,
		bool	flipLR,
		bool	flipUD,
		int32_t	rotateDeg )

Draw a WSG to the display.

Parameters

wsg	The WSG to draw to the display
xOff	The x offset to draw the WSG at
yOff	The y offset to draw the WSG at
flipLR	true to flip the image across the Y axis
flipUD	true to flip the image across the X axis
rotateDeg	The number of degrees to rotate clockwise, must be 0-359

drawWsgSimple()

void drawWsgSimple	(	const wsg_t *	wsg,
		int16_t	xOff,
		int16_t	yOff )

Draw a WSG to the display without flipping or rotation.

Parameters

wsg	The WSG to draw to the display
xOff	The x offset to draw the WSG at
yOff	The y offset to draw the WSG at

drawWsgSimpleScaled()

void drawWsgSimpleScaled	(	const wsg_t *	wsg,
		int16_t	xOff,
		int16_t	yOff,
		int16_t	xScale,
		int16_t	yScale )

Draw a WSG to the display without flipping or rotation.

Parameters

wsg	The WSG to draw to the display
xOff	The x offset to draw the WSG at
yOff	The y offset to draw the WSG at
xScale	The amount to scale the image horizontally
yScale	The amount to scale the image vertically

drawWsgTile()

void drawWsgTile	(	const wsg_t *	wsg,
		int32_t	xOff,
		int32_t	yOff )

Quickly copy a WSG to the display without flipping or rotation or transparency.

If the source WSG does have transparency, an indeterminate color will be drawn to the TFT

Parameters

wsg	The WSG to draw to the display
xOff	The x offset to draw the WSG at
yOff	The y offset to draw the WSG at

drawWsgSimpleHalf()

void drawWsgSimpleHalf	(	const wsg_t *	wsg,
		int16_t	xOff,
		int16_t	yOff )

Draw a WSG to the display without flipping or rotation at half size.

Parameters

wsg	The WSG to draw to the display
xOff	The x offset to draw the WSG at
yOff	The y offset to draw the WSG at