Glyph-cell blitting and text rendering for the ra8_gfx software rasteriser. More...

#include <stddef.h>
#include <stdint.h>
#include "ra8_err.h"
#include "ra8_gfx.h"
#include "ra8_gfx_internal.h"

Include dependency graph for ra8_gfx_text_glyph.c:

Enumerations
enum	ra8_gfx_glyph_bits_t : uint8_t { k_glyph_bits_per_byte = 8 , k_glyph_msb_index = 7 }
	Constants for monochrome glyph bit extraction. More...
enum	ra8_gfx_color_masks_t : uint32_t { k_mask_byte = 0xFFU }
	Per-channel masks for colour conversion. More...
enum	ra8_gfx_byte_idx_t : uint8_t { k_idx_r = 0 , k_idx_g = 1 }
	Per-byte indices for RGB888 packing. More...

Functions
static void	internal_blit_glyph_565 (int32_t x, int32_t y, int32_t gw, int32_t gh, uint32_t row_bytes, const uint8_t *gd, uint32_t fg, uint32_t bg)
	Blit one 1-bpp glyph cell into an RGB565 framebuffer, clipped on screen.
static void	internal_render_glyph (int32_t x, int32_t y, const ra8_gfx_font_t *font, uint8_t cp, uint32_t fg, uint32_t bg)
	Render a single glyph at (x,y).
ra8_err_t	ra8_gfx_text_out (int32_t x, int32_t y, const char str, const ra8_gfx_font_t font, uint32_t fg_color, uint32_t bg_color)
	Render a NUL-terminated ASCII string.
ra8_err_t	ra8_gfx_text_size (const char str, const ra8_gfx_font_t font, uint32_t out_w, uint32_t out_h)
	Compute rendered pixel dimensions of a string.

Detailed Description

Glyph-cell blitting and text rendering for the ra8_gfx software rasteriser.

Holds the text sub-responsibility of the software pixel-pusher: the 1-bpp glyph-cell blitters and the public text entry points (ra8_gfx_text_out, ra8_gfx_text_size). These share the single framebuffer binding (g_gfx_text_state) and the low-level packers/plotters with the core rasteriser TU (ra8_gfx_text.c) via ra8_gfx_internal.h.

Copyright: Copyright (c) 2026 Brighton Sikarskie SPDX-License-Identifier: MIT

Since: 0.1.0

Definition in file ra8_gfx_text_glyph.c.

Enumeration Type Documentation

◆ ra8_gfx_byte_idx_t

enum ra8_gfx_byte_idx_t : uint8_t

Per-byte indices for RGB888 packing.

Enumerator
k_idx_r	Index r.
k_idx_g	Index g.

Definition at line 45 of file ra8_gfx_text_glyph.c.

◆ ra8_gfx_color_masks_t

enum ra8_gfx_color_masks_t : uint32_t

Per-channel masks for colour conversion.

Enumerator
k_mask_byte	Mask byte.

Definition at line 37 of file ra8_gfx_text_glyph.c.

◆ ra8_gfx_glyph_bits_t

enum ra8_gfx_glyph_bits_t : uint8_t

Constants for monochrome glyph bit extraction.

Enumerator
k_glyph_bits_per_byte	Glyph bits per byte.
k_glyph_msb_index	Glyph msb index.

Definition at line 28 of file ra8_gfx_text_glyph.c.

Function Documentation

◆ internal_blit_glyph_565()

void internal_blit_glyph_565	(	int32_t	x,
		int32_t	y,
		int32_t	gw,
		int32_t	gh,
		uint32_t	row_bytes,
		const uint8_t *	gd,
		uint32_t	fg,
		uint32_t	bg )

static

Blit one 1-bpp glyph cell into an RGB565 framebuffer, clipped on screen.

The foreground and background colours are packed to RGB565 once, then each visible cell pixel stores the two pre-packed bytes directly – so the per-glyph colour packing (priv_gfx_text_pack_565 + per-channel extraction) and the per-pixel clip happen once each instead of once per pixel. The cell is clipped to the framebuffer up front (the same in-bounds set priv_gfx_text_plot would have written), and every on/off bit maps to the same colour, so the result is byte-identical to the per-pixel priv_gfx_text_plot path. The full cell is painted (foreground for set bits, background for clear bits), matching the per-pixel path's opaque cell.

Parameters

[in]	x	Glyph top-left x in framebuffer pixels.
[in]	y	Glyph top-left y in framebuffer pixels.
[in]	gw	Glyph cell width in pixels.
[in]	gh	Glyph cell height in pixels.
[in]	row_bytes	Bytes per glyph row in gd.
[in]	gd	Packed 1-bpp glyph bitmap (MSB-first within each byte).
[in]	fg	Foreground 32-bit colour (applied to set bits).
[in]	bg	Background 32-bit colour (applied to clear bits).

Precondition: The bound format is k_ra8_gfx_format_rgb565.; gd addresses at least gh*row_bytes bytes.

Postcondition: Every on-screen cell pixel holds fg (set bit) or bg (clear bit).; No off-screen pixel is modified.

Note: Not thread-safe unless documented otherwise.

Since: 0.1.0

Definition at line 79 of file ra8_gfx_text_glyph.c.

References g_gfx_text_state, k_glyph_bits_per_byte, k_glyph_msb_index, k_idx_g, k_idx_r, k_mask_byte, and priv_gfx_text_pack_565().

Referenced by internal_render_glyph().

◆ internal_render_glyph()

void internal_render_glyph	(	int32_t	x,
		int32_t	y,
		const ra8_gfx_font_t *	font,
		uint8_t	cp,
		uint32_t	fg,
		uint32_t	bg )

static

Render a single glyph at (x,y).

See implementation.

Parameters

[in]	x	See implementation.
[in]	y	See implementation.
[in]	font	See implementation.
[in]	cp	See implementation.
[in]	fg	See implementation.
[in]	bg	See implementation.

Precondition: Module state is consistent.; Module state is consistent.

Postcondition: Caller-visible state matches the documented contract.; Caller-visible state matches the documented contract.

Note: Not thread-safe unless documented otherwise.

Since: 0.1.0

Definition at line 145 of file ra8_gfx_text_glyph.c.

References ra8_gfx_font_t::bytes_per_glyph, ra8_gfx_font_t::first_codepoint, g_gfx_text_state, ra8_gfx_font_t::glyph_data, ra8_gfx_font_t::glyph_height, ra8_gfx_font_t::glyph_width, internal_blit_glyph_565(), k_glyph_bits_per_byte, k_glyph_msb_index, k_ra8_gfx_format_rgb565, ra8_gfx_font_t::last_codepoint, and priv_gfx_text_plot().

Referenced by ra8_gfx_text_out().

◆ ra8_gfx_text_out()

ra8_err_t ra8_gfx_text_out	(	int32_t	x,
		int32_t	y,
		const char *	str,
		const ra8_gfx_font_t *	font,
		uint32_t	fg_color,
		uint32_t	bg_color )

nodiscard

Render a NUL-terminated ASCII string.

Parameters

[in]	x,y	Top-left of the first glyph.
[in]	str	NUL-terminated ASCII string (NULL not allowed).
[in]	font	Font descriptor (NULL not allowed).
[in]	fg_color	Foreground colour.
[in]	bg_color	Background colour.

Returns: Error code.

Return values

k_ra8_ok	Rendered.
k_ra8_err_null_ptr	str or font was NULL.
k_ra8_err_not_initialized	ra8_gfx_init() was not called.

Precondition: ra8_gfx_init() returned k_ra8_ok.; font->glyph_data covers at least last-first+1 glyphs.

Postcondition: Glyph cells within bounds are filled with fg/bg colour pairs.

Since: 0.1.0

Definition at line 182 of file ra8_gfx_text_glyph.c.

References g_gfx_text_state, ra8_gfx_font_t::glyph_width, internal_render_glyph(), k_ra8_err_not_initialized, k_ra8_err_null_ptr, k_ra8_gfx_max_dim, and k_ra8_ok.

Referenced by ch_render(), cm_draw_status_bar(), er_draw_key_label(), er_nag_render(), er_text_left(), ls_text(), mg_render_status(), render_page(), sh_comic_render(), sh_cover_button(), sh_cover_render(), sh_draw_card(), sh_loading_overlay(), sh_reader_render(), sh_titlebar(), sh_toc_render(), wc_footer_render(), wc_status_render(), wc_tile_render(), wd_content_render(), wd_status_render(), wd_tabbar_render(), wd_text(), and wk_paint_text().

◆ ra8_gfx_text_size()

ra8_err_t ra8_gfx_text_size	(	const char *	str,
		const ra8_gfx_font_t *	font,
		uint32_t *	out_w,
		uint32_t *	out_h )

nodiscard

Compute rendered pixel dimensions of a string.

Parameters

[in]	str	ASCII string.
[in]	font	Font descriptor.
[out]	out_w	Receives total pixel width.
[out]	out_h	Receives total pixel height (font glyph height).

Returns: Error code.

Return values

k_ra8_ok	Measured.
k_ra8_err_null_ptr	Any argument was NULL.

Precondition: All pointer arguments are non-NULL.

Postcondition: *out_w and *out_h are written.

Since: 0.1.0

Definition at line 211 of file ra8_gfx_text_glyph.c.

References ra8_gfx_font_t::glyph_height, ra8_gfx_font_t::glyph_width, k_ra8_err_null_ptr, k_ra8_gfx_max_dim, and k_ra8_ok.

Referenced by er_text_right(), ls_text(), wd_size(), and wk_paint_size().

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

◆ ra8_gfx_byte_idx_t

◆ ra8_gfx_color_masks_t

◆ ra8_gfx_glyph_bits_t

Function Documentation

◆ internal_blit_glyph_565()

◆ internal_render_glyph()

◆ ra8_gfx_text_out()

◆ ra8_gfx_text_size()