CHGfx library

Wire-speed ST7735 graphics: a 16-colour framebuffer, DMA flushes, sprites, shapes, text and fonts. More...

Modules
	Configuration
	Screen geometry, the panel's wiring, colour modes and SPI dividers: the build options and the constants they define.
	Setup
	Starting the panel and changing its SPI clock, colour mode, orientation and scan rate.
	Palette
	The 16 colours the framebuffer's indices stand for, and a fade applied on top of them.
	Presenting the framebuffer
	Sending the framebuffer to the panel: whole or a rectangle, blocking or by DMA in the background, and waiting for it.
	Direct streaming
	Full-colour procedural frames computed straight into the DMA's buffers, with no framebuffer and no palette.
	Drawing
	The clip rectangle, pixels, lines, rectangles, circles and sprite blits, drawn into the 4 bpp framebuffer.
	Shapes
	Rounded rectangles, ellipses, dithered fills and in-place recolouring.
	Span sprites
	The compact run-length sprite format (sprite4): plain, scaled, recoloured and rotated.
	Row operations
	Scrolling and stamping whole framebuffer rows at word speed.
	Text
	Text in the built-in 5x7 font or any GFXfont: plain, scaled, measured, and outlined/shadowed banners.
	Fonts
	The bundled fonts in src/fonts/, the GFXfont format they use, and the built-in 5x7.
	Direct to the panel
	Talking to the ST7735 without the framebuffer: chip select, commands, address windows, DMA fills and raw blits.
	Internals and scratch
	The converters the Benchmark example measures, the flush's chunk buffers as scratch memory, and the frame size.
	The Gfx object
	The CHGfx class and its one instance, Gfx: the same API with Arduino-style names.
	Adafruit_GFX bridge
	CHGfx_GFX: an Adafruit_GFX whose drawing lands in CHGfx's framebuffer, from CHGfx_AdafruitGFX.h (needs the Adafruit GFX Library).

Detailed Description

Wire-speed ST7735 graphics: a 16-colour framebuffer, DMA flushes, sprites, shapes, text and fonts.

#include <CHGfx.h>

CHGfx drives the 128x128 ST7735S panel on SPI1 with DMA. It keeps a 4 bpp (16-colour) framebuffer of 8 KB in SRAM and expands it through a palette to the panel's 12 or 16 bpp while the DMA is already sending it, so a full frame goes out at 90 fps (16 bpp) or 119 fps (12 bpp). CHGame is built on it, and a sketch that includes CHGame.h has all of CHGfx too.

Everything is a plain C function (gfx_clear(), gfx_flushAsync() ...); the CHGfx class and its one instance Gfx are zero-cost forwarders for those who prefer Gfx.clear(0).

gfx_begin(GFX_DIV2, GFX_12BPP);
gfx_setPaletteEntry(1, gfx_rgb(255, 255, 255));
gfx_clear(0);
gfx_text(4, 4, "Hello", 1);
gfx_flush();

The rule that matters: drawing goes into the framebuffer, and the framebuffer is free to draw into only after gfx_wait() (or gfx_waitRow()), once the previous flush has finished reading it.

See also

The library's README (performance, the simulator, configuration and what everything costs), FONTS.md