wsgCanvas.h File Reference

Detailed Description

Provides a canvas to paint with low memory requirements.

Author

Jeremy Stintzcum (jerem.nosp@m.y.st.nosp@m.intzc.nosp@m.um@g.nosp@m.mail..nosp@m.com)

Version

1.0

Date

2025-09-02

Copyright

Copyright (c) 2025

Overview

The WSG Canvas system is a simple way of combining wsgs together to create a single sprite. Why is this useful? Well, it was initially designed for the swadgesonas, which would require loading a lot of individual WSGs and leaving them loaded, which would be pretty memory intensive. Instead, this canvas system allows for a WSG to be created once, and all the other WSGs applied over it are only loaded when the data is needed, and then immediately discarded. This is a much more efficient way to store swadgesonas, and will allow many of them to be on-screen at once.

Usage

Step one is to load up a canvas. Use canvasBlankInit() to create a blank canvas on which to paint, or load a normal WSG. Just note that any changes you make cannot be revered without re-initializing the WSG.

Next, use canvasDraw() to put WSGs onto the canvas. You can rotate, flip in both x and y, and position the WSG however you like on the canvas. Pixels outside of the boundaries of the canvas will be discarded, and transparent pixels will leave the color underneath to show through, allowing for complex layering.

Palettes are also supported, so things like custom hair colors can be applied without having to rely on a drawing function further down the line.

Two additional "simple" versions have been provided for when rotation and flipping aren't required.

Lastly, call freeWsg() when done with the canvas, just like any other WSG.

The canvas can be used like any WSG, so all wsg drawing functions work on it once it has been created.

// Create structs
wsg_t canvas;
 
// Initialize canvas
canvasBlankInit(&canvas, 280, 240, c444, true);
 
// Draw to the canvas normally
canvasDrawSimple(&canvas, KID_0_WSG, 40, 48);
 
// Draw to the canvas with a palette
wsgPalette_t palette;
wsgPaletteReset(&palette);
canvasDrawPal(&canvas, KID_1_WSG, 160, 48, true, false, 15, palette);
 
// Clean up
freeWsg(&canvas);

Go to the source code of this file.

Functions
void	canvasBlankInit (wsg_t *canvas, int width, int height, paletteColor_t startColor, bool spiRam)
	Initializes a blank canvas to the dimensions and color provided.
void	canvasDrawSimple (wsg_t *canvas, cnfsFileIdx_t image, int startX, int startY)
	Draws a image to the canvas at the specified coordinates relative to the canvas.
void	canvasDrawSimplePal (wsg_t *canvas, cnfsFileIdx_t image, int startX, int startY, wsgPalette_t *pal)
	Draws a image to the canvas at the specified coordinates relative to the canvas and applies a palette.
void	canvasDraw (wsg_t *canvas, cnfsFileIdx_t image, int startX, int startY, bool flipX, bool flipY, int32_t rotateDeg)
	Draws an image to the canvas at a specified angle.
void	canvasDrawPal (wsg_t *canvas, cnfsFileIdx_t image, int startX, int startY, bool flipX, bool flipY, int32_t rotateDeg, wsgPalette_t *pal)
	Draws an image to the canvas at a specified angle.

Function Documentation

canvasBlankInit()

void canvasBlankInit	(	wsg_t *	canvas,
		int	width,
		int	height,
		paletteColor_t	startColor,
		bool	spiRam )

Initializes a blank canvas to the dimensions and color provided.

Parameters

canvas	WSG to save the canvas too. Use a standard wsg_t and provide the pointer
width	Width in pixels of the desired canvas
height	Height in pixels of the desired canvas
startColor	The initial color. Can be any paletteColor_t including cTransparent
spiRam	Whether or not to load the pixel data into SPIRAM.

canvasDrawSimple()

void canvasDrawSimple	(	wsg_t *	canvas,
		cnfsFileIdx_t	image,
		int	startX,
		int	startY )

Draws a image to the canvas at the specified coordinates relative to the canvas.

Parameters

canvas	WSG to save changes to. Will work with any WSG, cannot be reverted
image	New cnfsFileIdx_t to apply to the canvas
startX	X position on canvas. Negative moves left, positive moves right. Pixels not on canvas are cropped.
startY	Y position on canvas. Negative moves left, positive moves right. Pixels not on canvas are cropped.

canvasDrawSimplePal()

void canvasDrawSimplePal	(	wsg_t *	canvas,
		cnfsFileIdx_t	image,
		int	startX,
		int	startY,
		wsgPalette_t *	pal )

Draws a image to the canvas at the specified coordinates relative to the canvas and applies a palette.

Parameters

canvas	WSG to save changes to. Will work with any WSG, cannot be reverted
image	New cnfsFileIdx_t to apply to the canvas
startX	X position on canvas. Negative moves left, positive moves right. Pixels not on canvas are cropped.
startY	Y position on canvas. Negative moves left, positive moves right. Pixels not on canvas are cropped.
pal	Palette data to use to transform the image

canvasDraw()

void canvasDraw	(	wsg_t *	canvas,
		cnfsFileIdx_t	image,
		int	startX,
		int	startY,
		bool	flipX,
		bool	flipY,
		int32_t	rotateDeg )

Draws an image to the canvas at a specified angle.

Parameters

canvas	WSG to save changes to. Will work with any WSG, cannot be reverted
image	New cnfsFileIdx_t to apply to the canvas
startX	X position on canvas. Negative moves left, positive moves right. Pixels not on canvas are cropped.
startY	Y position on canvas. Negative moves left, positive moves right. Pixels not on canvas are cropped.
flipX	Flips applied image in the x direction
flipY	Flips applied image in the Y direction
rotateDeg	Angle to draw the image at

canvasDrawPal()

void canvasDrawPal	(	wsg_t *	canvas,
		cnfsFileIdx_t	image,
		int	startX,
		int	startY,
		bool	flipX,
		bool	flipY,
		int32_t	rotateDeg,
		wsgPalette_t *	pal )

Draws an image to the canvas at a specified angle.

Parameters

canvas	WSG to save changes to. Will work with any WSG, cannot be reverted
image	New cnfsFileIdx_t to apply to the canvas
startX	X position on canvas. Negative moves left, positive moves right. Pixels not on canvas are cropped.
startY	Y position on canvas. Negative moves left, positive moves right. Pixels not on canvas are cropped.
flipX	Flips applied image in the x direction
flipY	Flips applied image in the Y direction
rotateDeg	Angle to draw the image at
pal	Palette data to use to transform the image