Tap-driven pan/zoom viewer over a tiled manga page (ereader_manga). More...

#include "mg_reader.h"
#include <stddef.h>
#include <stdint.h>
#include "jof.h"
#include "ra8_check.h"
#include "ra8_err.h"
#include "ra8_gfx.h"
#include "ra8_gfx_font.h"
#include "ra8_tile_cache.h"

Include dependency graph for mg_reader.c:

Enumerations
enum	mg_color_t : uint32_t { k_mg_col_letterbox = 0x000000U , k_mg_col_status_bg = 0x141420U , k_mg_col_status_fg = 0xFFFFFFU , k_mg_col_minimap_bg = 0x202830U , k_mg_col_minimap_fg = 0x808890U , k_mg_col_minimap_view = 0xFFE000U }
	Chrome palette (0x00RRGGBB; ra8_gfx packs to RGB565). More...
enum	mg_metric_t : uint16_t { k_mg_status_cap = 48U , k_mg_status_text_x = 16U , k_mg_glyph_h = 16U , k_mg_dec_max = 12U , k_mg_i32_dec_digits = 10U }
	Text / formatting metrics. More...
enum	mg_bits_t : uint8_t { k_mg_dec_ten = 10U , k_mg_r_drop = 3U , k_mg_g_drop = 2U , k_mg_r_sh = 11U , k_mg_g_sh = 5U }
	gray8 -> RGB565 field shifts and the decimal radix. More...
enum	mg_fnv_t : uint32_t { k_mg_fnv_offset = 2166136261U , k_mg_fnv_prime = 16777619U }
	FNV-1a-32 constants. More...
enum	mg_pixfmt_t : uint8_t { k_mg_gray8_bpp = 1U }
	The single JOF pixel format the reader can blit. More...

Functions
static int32_t	mg_scale (const mg_reader_t *r)
	Decimation factor for the active zoom (1 at 1:1, fit_factor at fit).
static int32_t	mg_content_h (const mg_reader_t *r)
	Content-area height below the status bar, panel px.
static void	mg_region (const mg_reader_t r, int32_t x0, int32_t y0, int32_t x1, int32_t *y1)
	Source page rectangle currently shown, clamped to the page.
static void	mg_offsets (const mg_reader_t r, int32_t ox, int32_t *oy)
	Panel-pixel offset that centres the shown region in the content area.
static bool	mg_map (const mg_reader_t r, int32_t s, int32_t ox, int32_t oy, int32_t sx, int32_t sy, int32_t dx, int32_t *dy)
	Map one caller-clipped page pixel to the panel; false if off-grid.
static uint16_t	mg_g565 (uint8_t g)
	Pack a gray8 sample into an RGB565 pixel.
static void	mg_clamp (mg_reader_t *r)
	Viewport-clamp the reader for the active zoom (fit pins to 0,0).
static void	mg_blit_tile (mg_reader_t r, const ra8_tile_t t, uint16_t tx, uint16_t ty, int32_t s, int32_t ox, int32_t oy, const int32_t reg[4])
	Blit one pinned gray8 tile's viewport overlap into the framebuffer.
static void	mg_tiles_of_region (const mg_reader_t *r, const int32_t reg[4], uint16_t out[4])
	Inclusive tile rect {tx0,ty0,tx1,ty1} covering a page region.
static ra8_err_t	mg_render_page (mg_reader_t *r)
	Page every tile overlapping the viewport through the cache and blit.
static ra8_err_t	mg_render_status (mg_reader_t *r)
	Draw the top status bar (background band + the status string).
static void	mg_render_minimap (mg_reader_t *r)
	Draw the bottom-right minimap: the page bounds + the viewport rect.
ra8_err_t	mg_reader_render (mg_reader_t *r)
	Render the current viewport + chrome into the framebuffer.
ra8_err_t	mg_reader_prefetch (mg_reader_t *r)
	Warm the tiles one step ahead of the last pan (predictive prefetch).
static ra8_tile_pan_dir_t	mg_pan_dir (int32_t dx, int32_t dy)
	Pan direction of a (dx,dy) step (exactly one axis is non-zero).
static bool	mg_pan (mg_reader_t *r, int32_t dx, int32_t dy)
	Slide the viewport by (dx,dy) page px; false if pinned / at fit.
mg_zone_t	mg_zone_hit (const mg_reader_t *r, int32_t x, int32_t y)
	Classify a panel coordinate into its tap-zone.
bool	mg_reader_toggle_zoom (mg_reader_t *r)
	Toggle the zoom between 1:1 and fit-page (SW-button entry point).
bool	mg_reader_tap (mg_reader_t *r, int32_t x, int32_t y)
	Apply a tap: pan or toggle zoom, and report whether state changed.
static uint32_t	mg_append_uint (char *buf, uint32_t cap, uint32_t pos, int32_t val)
	Append an unsigned decimal (from a signed val, clamped >= 0).
static uint32_t	mg_append_str (char buf, uint32_t cap, uint32_t pos, const char s, uint32_t length)
	Append an exact immutable fragment, bounded by `cap`.
ra8_err_t	mg_reader_status (const mg_reader_t r, char buf, uint32_t cap)
	Format the status-bar string ("MANGA 1:1 x=.. y=..").
uint32_t	mg_fnv1a (const void *buf, uint32_t len)
	FNV-1a-32 over a byte buffer (framebuffer render hash for the banner).
static uint8_t	mg_fit_factor (const mg_reader_t *r)
	Smallest integer decimation that fits the page in the content area.
static void	mg_reader_bind (mg_reader_t r, const mg_reader_cfg_t cfg)
	Populate reader state from an already-validated config (no checks).
static ra8_err_t	mg_reader_check_ptrs (const mg_reader_t r, const mg_reader_cfg_t cfg)
	Null-guard the init inputs (5 preconditions, NASA Rule 5).
static ra8_err_t	mg_reader_check_geometry (const mg_reader_cfg_t *cfg)
	Validate framebuffer + atlas geometry; reject non-gray8 atlases (#339).
ra8_err_t	mg_reader_init (mg_reader_t r, const mg_reader_cfg_t cfg)
	Bind a viewer to a produced atlas and reset it to 1:1 top-left.
ra8_err_t	mg_tile_decode (void ctx, const ra8_tile_key_t key, uint8_t cell, uint32_t cell_bytes, uint16_t out_w, uint16_t *out_h)
	Tile-cache decode-on-miss callback: page one atlas tile into a cell.

Variables
static const char	k_mg_tag [] = "mg_reader"
	Log tag for the reader's null-pointer guards.

Detailed Description

Tap-driven pan/zoom viewer over a tiled manga page (ereader_manga).

Tag: [Ring 6 / APP] {World: NS}

Implementation of the presentation model declared in inc/mg_reader.h. The reader owns no hardware: it maps page pixels to panel pixels, pages the covered tiles through ra8_tile_cache one at a time, packs gray8 to RGB565, and draws the chrome through ra8_gfx – so the same render runs on the firmware, under ra8_emulator, and in the host unit test.

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

Since: 0.1.0

Definition in file mg_reader.c.

Enumeration Type Documentation

◆ mg_bits_t

enum mg_bits_t : uint8_t

gray8 -> RGB565 field shifts and the decimal radix.

Since: 0.1.0

Enumerator
k_mg_dec_ten	Decimal radix.
k_mg_r_drop	gray8 -> 5-bit field shift.
k_mg_g_drop	gray8 -> 6-bit field shift.
k_mg_r_sh	RGB565 red field shift.
k_mg_g_sh	RGB565 green field shift.

Definition at line 67 of file mg_reader.c.

◆ mg_color_t

enum mg_color_t : uint32_t

Chrome palette (0x00RRGGBB; ra8_gfx packs to RGB565).

Since: 0.1.0

Enumerator
k_mg_col_letterbox	Framebuffer clear (page margins).
k_mg_col_status_bg	Status-bar background.
k_mg_col_status_fg	Status-bar text.
k_mg_col_minimap_bg	Minimap page area.
k_mg_col_minimap_fg	Minimap frame.
k_mg_col_minimap_view	Minimap current-viewport rect.

Definition at line 40 of file mg_reader.c.

◆ mg_fnv_t

enum mg_fnv_t : uint32_t

FNV-1a-32 constants.

Since: 0.1.0

Enumerator
k_mg_fnv_offset	FNV-1a-32 offset basis.
k_mg_fnv_prime	FNV-1a-32 prime.

Definition at line 80 of file mg_reader.c.

◆ mg_metric_t

enum mg_metric_t : uint16_t

Text / formatting metrics.

Since: 0.1.0

Enumerator
k_mg_status_cap	Status-string scratch capacity.
k_mg_status_text_x	Status text left inset, panel px.
k_mg_glyph_h	ra8_gfx_font_8x16 glyph height.
k_mg_dec_max	Decimal digit scratch length.
k_mg_i32_dec_digits	Maximum non-negative int32_t digits.

Definition at line 54 of file mg_reader.c.

◆ mg_pixfmt_t

enum mg_pixfmt_t : uint8_t

The single JOF pixel format the reader can blit.

Every blit path here (mg_blit_tile via mg_g565) reads one byte per pixel and expands it as gray8. A JOF atlas may instead declare bpp 3 (RGB888) or 4 (RGBA8888) – jof_produce follows the source decoder's channel count – so mg_reader_init fails closed on anything but k_mg_gray8_bpp rather than mis-reading a colour tile one byte per pixel and rendering garbage (#339).

Since: 0.1.0

Enumerator
k_mg_gray8_bpp	The only bytes-per-pixel the reader supports.

Definition at line 98 of file mg_reader.c.

Function Documentation

◆ mg_append_str()

uint32_t mg_append_str	(	char *	buf,
		uint32_t	cap,
		uint32_t	pos,
		const char *	s,
		uint32_t	length )

static

Append an exact immutable fragment, bounded by cap.

Definition at line 512 of file mg_reader.c.

Referenced by mg_reader_status().

◆ mg_append_uint()

uint32_t mg_append_uint	(	char *	buf,
		uint32_t	cap,
		uint32_t	pos,
		int32_t	val )

static

Append an unsigned decimal (from a signed val, clamped >= 0).

Definition at line 488 of file mg_reader.c.

References k_mg_dec_max, k_mg_dec_ten, and k_mg_i32_dec_digits.

Referenced by mg_reader_status().

◆ mg_blit_tile()

void mg_blit_tile	(	mg_reader_t *	r,
		const ra8_tile_t *	t,
		uint16_t	tx,
		uint16_t	ty,
		int32_t	s,
		int32_t	ox,
		int32_t	oy,
		const int32_t	reg[4] )

static

Blit one pinned gray8 tile's viewport overlap into the framebuffer.

Definition at line 220 of file mg_reader.c.

References mg_reader_t::fb, mg_reader_t::fb_w, ra8_tile_t::height, mg_g565(), mg_map(), ra8_tile_t::pixels, mg_reader_t::tile_h, mg_reader_t::tile_w, and ra8_tile_t::width.

Referenced by mg_render_page().

◆ mg_clamp()

void mg_clamp ( mg_reader_t * r )

static

Viewport-clamp the reader for the active zoom (fit pins to 0,0).

Definition at line 188 of file mg_reader.c.

References mg_reader_t::fb_w, k_mg_zoom_fit, mg_content_h(), mg_reader_t::page_h, mg_reader_t::page_w, mg_reader_t::view_x, mg_reader_t::view_y, and mg_reader_t::zoom.

Referenced by mg_pan(), mg_reader_bind(), and mg_reader_toggle_zoom().

◆ mg_content_h()

int32_t mg_content_h ( const mg_reader_t * r )

static

Content-area height below the status bar, panel px.

Definition at line 113 of file mg_reader.c.

References mg_reader_t::fb_h, and k_mg_statusbar_h.

Referenced by mg_clamp(), mg_fit_factor(), mg_offsets(), and mg_region().

◆ mg_fit_factor()

uint8_t mg_fit_factor ( const mg_reader_t * r )

static

Smallest integer decimation that fits the page in the content area.

Definition at line 554 of file mg_reader.c.

References mg_reader_t::fb_w, mg_content_h(), mg_reader_t::page_h, and mg_reader_t::page_w.

Referenced by mg_reader_bind().

◆ mg_fnv1a()

uint32_t mg_fnv1a	(	const void *	buf,
		uint32_t	len )

nodiscard

FNV-1a-32 over a byte buffer (framebuffer render hash for the banner).

Parameters

[in]	buf	Bytes to hash.
[in]	len	Byte count.

Returns: uint32_t The FNV-1a-32 digest.

Return values

2166136261 The offset basis, when len is 0 (empty digest).

Precondition: buf holds len readable bytes (or len is 0).; None.

Postcondition: No state is mutated.; The digest is deterministic across host / ra8_emulator / silicon.

Note: Thread-safe (pure).

Since: 0.1.0

Definition at line 540 of file mg_reader.c.

References k_mg_fnv_offset, and k_mg_fnv_prime.

Referenced by mg_print_banner().

◆ mg_g565()

uint16_t mg_g565 ( uint8_t g )

static

Pack a gray8 sample into an RGB565 pixel.

Definition at line 179 of file mg_reader.c.

References k_mg_g_drop, k_mg_g_sh, k_mg_r_drop, and k_mg_r_sh.

Referenced by mg_blit_tile().

◆ mg_map()

bool mg_map	(	const mg_reader_t *	r,
		int32_t	s,
		int32_t	ox,
		int32_t	oy,
		int32_t	sx,
		int32_t	sy,
		int32_t *	dx,
		int32_t *	dy )

static

Map one caller-clipped page pixel to the panel; false if off-grid.

Definition at line 154 of file mg_reader.c.

References k_mg_statusbar_h, mg_reader_t::view_x, and mg_reader_t::view_y.

Referenced by mg_blit_tile().

◆ mg_offsets()

void mg_offsets	(	const mg_reader_t *	r,
		int32_t *	ox,
		int32_t *	oy )

static

Panel-pixel offset that centres the shown region in the content area.

Definition at line 137 of file mg_reader.c.

References mg_reader_t::fb_w, mg_content_h(), mg_region(), and mg_scale().

Referenced by mg_render_page().

◆ mg_pan()

bool mg_pan	(	mg_reader_t *	r,
		int32_t	dx,
		int32_t	dy )

static

Slide the viewport by (dx,dy) page px; false if pinned / at fit.

Definition at line 402 of file mg_reader.c.

References k_mg_zoom_fit, k_ra8_tile_pan_none, mg_reader_t::last_pan, mg_clamp(), mg_pan_dir(), mg_reader_t::view_x, mg_reader_t::view_y, and mg_reader_t::zoom.

Referenced by mg_reader_tap().

◆ mg_pan_dir()

ra8_tile_pan_dir_t mg_pan_dir	(	int32_t	dx,
		int32_t	dy )

static

Pan direction of a (dx,dy) step (exactly one axis is non-zero).

Definition at line 387 of file mg_reader.c.

References k_ra8_tile_pan_down, k_ra8_tile_pan_left, k_ra8_tile_pan_right, and k_ra8_tile_pan_up.

Referenced by mg_pan().

◆ mg_reader_bind()

void mg_reader_bind	(	mg_reader_t *	r,
		const mg_reader_cfg_t *	cfg )

static

Populate reader state from an already-validated config (no checks).

Definition at line 568 of file mg_reader.c.

References mg_reader_cfg_t::cache, mg_reader_cfg_t::fb, mg_reader_cfg_t::fb_h, mg_reader_cfg_t::fb_w, mg_reader_t::fit_factor, jof_info_t::height, mg_reader_cfg_t::image_id, mg_reader_cfg_t::info, k_mg_zoom_full, k_ra8_tile_pan_none, mg_clamp(), mg_fit_factor(), jof_info_t::tile_cols, jof_info_t::tile_h, jof_info_t::tile_rows, jof_info_t::tile_w, and jof_info_t::width.

Referenced by mg_reader_init().

◆ mg_reader_check_geometry()

ra8_err_t mg_reader_check_geometry ( const mg_reader_cfg_t * cfg )

static

Validate framebuffer + atlas geometry; reject non-gray8 atlases (#339).

Definition at line 601 of file mg_reader.c.

References jof_info_t::bpp, mg_reader_cfg_t::fb_h, mg_reader_cfg_t::fb_w, jof_info_t::height, mg_reader_cfg_t::info, k_mg_gray8_bpp, k_mg_statusbar_h, k_mg_tag, k_ra8_err_invalid_size, k_ra8_err_not_supported, k_ra8_ok, ra8_log_error, jof_info_t::tile_h, jof_info_t::tile_w, and jof_info_t::width.

Referenced by mg_reader_init().

◆ mg_reader_check_ptrs()

ra8_err_t mg_reader_check_ptrs	(	const mg_reader_t *	r,
		const mg_reader_cfg_t *	cfg )

static

Null-guard the init inputs (5 preconditions, NASA Rule 5).

Definition at line 590 of file mg_reader.c.

References mg_reader_cfg_t::cache, mg_reader_cfg_t::fb, mg_reader_cfg_t::info, k_mg_tag, k_ra8_ok, and RA8_CHECK_NULL_PTR.

Referenced by mg_reader_init().

◆ mg_reader_init()

ra8_err_t mg_reader_init	(	mg_reader_t *	r,
		const mg_reader_cfg_t *	cfg )

nodiscard

Bind a viewer to a produced atlas and reset it to 1:1 top-left.

Parameters

[out]	r	Reader state to populate.
[in]	cfg	Framebuffer + cache + parsed atlas geometry.

Returns: ra8_err_t Error code.

Return values

k_ra8_ok	Reader ready; viewport at (0,0), zoom 1:1.
k_ra8_err_null_ptr	`r`, `cfg`, or a required `cfg` field NULL.
k_ra8_err_invalid_size	`cfg` geometry is zero / smaller than the fb.
k_ra8_err_not_supported	`cfg->info->bpp` is not 1 (gray8); the blit path reads one byte per pixel, so a colour atlas is rejected rather than mis-rendered.

Precondition: cfg->info came from a successful jof_parse.; cfg->info->bpp == 1 (gray8); colour atlases are unsupported.; cfg->fb covers fb_w * fb_h RGB565 pixels.

Postcondition: On success the viewport is clamped inside the page.; On any error r is left unbound.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 619 of file mg_reader.c.

References k_ra8_ok, mg_reader_bind(), mg_reader_check_geometry(), and mg_reader_check_ptrs().

Referenced by main().

◆ mg_reader_prefetch()

ra8_err_t mg_reader_prefetch ( mg_reader_t * r )

nodiscard

Warm the tiles one step ahead of the last pan (predictive prefetch).

Called in the idle window after mg_reader_render presents a panned frame, so the next tiles the viewport will expose are decoded into the cache before the next pan needs them – the image counterpart of the chapter-text read-ahead (book_src_prefetch_chapter). Warms the lead tile row/column in r->last_pan through ra8_tile_cache_prefetch_pan, sizing the budget from the cache's spare capacity (capacity - currently-visible tiles) so a prefetch can never evict an on-screen tile. A no-op when the last action was not a moving pan (last_pan == k_ra8_tile_pan_none – the initial frame, a zoom toggle, a pan clamped at the page edge, or fit-page zoom where a pan is a no-op), or when the cache has no spare capacity. Transparent: warming changes only residency, so the next mg_reader_render is byte-identical.

Parameters

[in,out] r Bound reader (its last_pan seeds the direction).

Returns: ra8_err_t Error code.

Return values

k_ra8_ok	Prefetch ran (possibly warming zero tiles).
k_ra8_err_null_ptr	`r` or its cache was NULL.
k_ra8_err_*	Propagated from ra8_tile_cache_prefetch_pan.

Precondition: r was populated by mg_reader_init.; The tile cache can decode the lead-edge tiles.

Postcondition: No on-screen tile resident after the last render is evicted.; r->fb and the viewport state are unchanged.

Note: Not thread-safe. Single-threaded read-ahead only.

See also: mg_reader_render()

Since: 0.1.0

Definition at line 349 of file mg_reader.c.

References mg_reader_t::cache, mg_reader_t::image_id, k_mg_tag, k_ra8_ok, k_ra8_tile_pan_none, mg_reader_t::last_pan, mg_region(), mg_tiles_of_region(), RA8_CHECK_NULL_PTR, ra8_tile_cache_capacity(), ra8_tile_cache_prefetch_pan(), mg_reader_t::tile_cols, and mg_reader_t::tile_rows.

Referenced by mg_poll_touch().

◆ mg_reader_render()

ra8_err_t mg_reader_render ( mg_reader_t * r )

nodiscard

Render the current viewport + chrome into the framebuffer.

Clears the framebuffer, pages every tile overlapping the viewport through the cache (get/blit/put one at a time so a small cache evicts across the frame), packs gray8 to RGB565 with nearest- neighbour decimation at fit-page zoom, then draws the status bar and the minimap overlay.

Parameters

[in,out] r Bound reader.

Returns: ra8_err_t Error code.

Return values

k_ra8_ok	The framebuffer holds the current view.
k_ra8_err_null_ptr	`r` or its framebuffer was NULL.
k_ra8_err_*	Propagated from the tile cache / gfx.

Precondition: r was populated by mg_reader_init and ra8_gfx is bound to r->fb.; The tile cache can decode every covered tile.

Postcondition: On success r->fb holds the rendered screen.; Every tile pinned during the frame was released.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 332 of file mg_reader.c.

References mg_reader_t::fb, k_mg_col_letterbox, k_mg_tag, k_ra8_ok, mg_render_minimap(), mg_render_page(), mg_render_status(), RA8_CHECK_NULL_PTR, and ra8_gfx_clear().

Referenced by main(), and mg_poll_touch().

◆ mg_reader_status()

ra8_err_t mg_reader_status	(	const mg_reader_t *	r,
		char *	buf,
		uint32_t	cap )

nodiscard

Format the status-bar string ("MANGA 1:1 x=.. y=..").

Parameters

[in]	r	Bound reader.
[out]	buf	Destination, NUL-terminated on return.
[in]	cap	Capacity of `buf` (>= 1).

Returns: ra8_err_t Error code.

Return values

k_ra8_ok	The status text was written.
k_ra8_err_null_ptr	`r` or `buf` was NULL.
k_ra8_err_invalid_size	`cap` was 0.

Precondition: r was populated by mg_reader_init.; buf holds cap writable bytes.

Postcondition: buf is NUL-terminated within cap.; No reader state is mutated.

Note: Thread-safe for distinct buffers.

Since: 0.1.0

Definition at line 522 of file mg_reader.c.

References k_mg_tag, k_mg_zoom_full, k_ra8_err_invalid_size, k_ra8_ok, mg_append_str(), mg_append_uint(), RA8_CHECK_NULL_PTR, mg_reader_t::view_x, mg_reader_t::view_y, and mg_reader_t::zoom.

Referenced by mg_render_status().

◆ mg_reader_tap()

bool mg_reader_tap	(	mg_reader_t *	r,
		int32_t	x,
		int32_t	y )

nodiscard

Apply a tap: pan or toggle zoom, and report whether state changed.

Maps (x,y) through mg_zone_hit, then mutates the viewport (an edge zone, clamped inside the page) or the zoom (the centre zone). A pan already at the page edge, or a tap on no zone, leaves the state unchanged and returns false so the caller can skip the redraw.

Parameters

[in,out]	r	Bound reader.
[in]	x	Tap X, panel pixels.
[in]	y	Tap Y, panel pixels.

Returns: bool Whether the viewport or zoom changed.

Return values

true	State changed; the caller should re-render.
false	Tap hit nothing actionable (no redraw needed).

Precondition: r was populated by mg_reader_init.; x and y are panel coordinates.

Postcondition: On true the viewport/zoom reflects the tap, clamped inside the page.; On false r is byte-for-byte unchanged.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 461 of file mg_reader.c.

References k_mg_pan_step, k_mg_zone_none, k_mg_zone_pan_down, k_mg_zone_pan_left, k_mg_zone_pan_right, k_mg_zone_pan_up, k_mg_zone_zoom, mg_pan(), mg_reader_toggle_zoom(), and mg_zone_hit().

Referenced by mg_poll_touch().

◆ mg_reader_toggle_zoom()

bool mg_reader_toggle_zoom ( mg_reader_t * r )

nodiscard

Toggle the zoom between 1:1 and fit-page (SW-button entry point).

Parameters

[in,out] r Bound reader.

Returns: bool Whether the zoom was toggled.

Return values

true	The zoom state flipped (the normal case).
false	`r` was NULL (nothing toggled).

Precondition: r was populated by mg_reader_init.; None.

Postcondition: On true r->zoom is the other mg_zoom_t member.; The viewport is re-clamped for the new zoom.

Note: Not thread-safe.

Since: 0.1.0

Definition at line 450 of file mg_reader.c.

References k_mg_zoom_fit, k_mg_zoom_full, k_ra8_tile_pan_none, mg_reader_t::last_pan, mg_clamp(), and mg_reader_t::zoom.

Referenced by mg_reader_tap().

◆ mg_region()

void mg_region	(	const mg_reader_t *	r,
		int32_t *	x0,
		int32_t *	y0,
		int32_t *	x1,
		int32_t *	y1 )

static

Source page rectangle currently shown, clamped to the page.

Definition at line 119 of file mg_reader.c.

References mg_reader_t::fb_w, mg_content_h(), mg_scale(), mg_reader_t::page_h, mg_reader_t::page_w, mg_reader_t::view_x, and mg_reader_t::view_y.

Referenced by mg_offsets(), mg_reader_prefetch(), mg_render_minimap(), and mg_render_page().

◆ mg_render_minimap()

void mg_render_minimap ( mg_reader_t * r )

static

Draw the bottom-right minimap: the page bounds + the viewport rect.

Definition at line 306 of file mg_reader.c.

References mg_reader_t::fb_h, mg_reader_t::fb_w, k_mg_col_minimap_bg, k_mg_col_minimap_fg, k_mg_col_minimap_view, k_mg_minimap_h, k_mg_minimap_in, k_mg_minimap_pad, k_mg_minimap_w, mg_region(), mg_reader_t::page_h, mg_reader_t::page_w, and ra8_gfx_rect().

Referenced by mg_reader_render().

◆ mg_render_page()

ra8_err_t mg_render_page ( mg_reader_t * r )

static

Page every tile overlapping the viewport through the cache and blit.

Definition at line 262 of file mg_reader.c.

References mg_reader_t::cache, mg_reader_t::image_id, k_ra8_ok, mg_blit_tile(), mg_offsets(), mg_region(), mg_scale(), mg_tiles_of_region(), ra8_tile_t::pixels, ra8_tile_cache_get(), and ra8_tile_cache_put().

Referenced by mg_reader_render().

◆ mg_render_status()

ra8_err_t mg_render_status ( mg_reader_t * r )

static

Draw the top status bar (background band + the status string).

Definition at line 291 of file mg_reader.c.

References mg_reader_t::fb_w, k_mg_col_status_bg, k_mg_col_status_fg, k_mg_glyph_h, k_mg_status_cap, k_mg_status_text_x, k_mg_statusbar_h, mg_reader_status(), ra8_gfx_font_8x16, ra8_gfx_rect(), and ra8_gfx_text_out().

Referenced by mg_reader_render().

◆ mg_scale()

int32_t mg_scale ( const mg_reader_t * r )

static

Decimation factor for the active zoom (1 at 1:1, fit_factor at fit).

Definition at line 107 of file mg_reader.c.

References mg_reader_t::fit_factor, k_mg_zoom_fit, and mg_reader_t::zoom.

Referenced by mg_offsets(), mg_region(), and mg_render_page().

◆ mg_tile_decode()

ra8_err_t mg_tile_decode	(	void *	ctx,
		const ra8_tile_key_t *	key,
		uint8_t *	cell,
		uint32_t	cell_bytes,
		uint16_t *	out_w,
		uint16_t *	out_h )

nodiscard

Tile-cache decode-on-miss callback: page one atlas tile into a cell.

Matches ra8_tile_decode_fn. Reads key->tile_x / tile_y and reads that tile out of the atlas through jof_read_tile (raw copy or deflate inflate) into cell, reporting the tile's clamped dimensions.

Parameters

[in]	ctx	A mg_tile_src_t* bound at cache init.
[in]	key	The tile to decode.
[out]	cell	Destination cell (cell_bytes writable).
[in]	cell_bytes	Cell capacity in bytes.
[out]	out_w	Decoded tile width, pixels.
[out]	out_h	Decoded tile height, pixels.

Returns: ra8_err_t k_ra8_ok on success, or the read-tile error verbatim.

Return values

k_ra8_ok	Tile decoded into `cell`.
k_ra8_err_null_ptr	A required pointer was NULL.
k_ra8_err_*	Propagated from jof_read_tile.

Precondition: ctx points at a live mg_tile_src_t.; cell holds cell_bytes writable bytes.

Postcondition: On success (*out_w) * (*out_h) gray8 bytes are valid in cell.; On any error cell content is unspecified.

Note: Not thread-safe (shares the read-tile scratch).

Since: 0.1.0

Definition at line 633 of file mg_reader.c.

References mg_tile_src_t::info, jof_read_tile(), k_mg_tag, mg_tile_src_t::pread, mg_tile_src_t::pread_ctx, RA8_CHECK_NULL_PTR, mg_tile_src_t::scratch, mg_tile_src_t::scratch_cap, ra8_tile_key_t::tile_x, and ra8_tile_key_t::tile_y.

Referenced by mg_setup_cache().

◆ mg_tiles_of_region()

void mg_tiles_of_region	(	const mg_reader_t *	r,
		const int32_t	reg[4],
		uint16_t	out[4] )

static

Inclusive tile rect {tx0,ty0,tx1,ty1} covering a page region.

Definition at line 253 of file mg_reader.c.

References mg_reader_t::tile_h, and mg_reader_t::tile_w.

Referenced by mg_reader_prefetch(), and mg_render_page().

◆ mg_zone_hit()

mg_zone_t mg_zone_hit	(	const mg_reader_t *	r,
		int32_t	x,
		int32_t	y )

nodiscard

Classify a panel coordinate into its tap-zone.

Pure hit-test with no side effects: the centre rectangle (inside all four edge bands, below the status bar) is the zoom zone; each edge band is its pan zone; the status bar and any gap map to k_mg_zone_none.

Parameters

[in]	r	Bound reader (for the framebuffer extent).
[in]	x	Tap X, panel pixels.
[in]	y	Tap Y, panel pixels.

Returns: mg_zone_t The zone (x,y) falls in.

Return values

k_mg_zone_none	Status bar / outside the content area.
k_mg_zone_pan_*	An edge band.
k_mg_zone_zoom	The centre.

Precondition: r was populated by mg_reader_init.; x and y are panel coordinates.

Postcondition: No state is mutated.; The result is one mg_zone_t member.

Note: Thread-safe (pure over its inputs).

Since: 0.1.0

Definition at line 417 of file mg_reader.c.

References mg_reader_t::fb_h, mg_reader_t::fb_w, k_mg_edge_band, k_mg_statusbar_h, k_mg_zone_none, k_mg_zone_pan_down, k_mg_zone_pan_left, k_mg_zone_pan_right, k_mg_zone_pan_up, and k_mg_zone_zoom.

Referenced by mg_reader_tap().

Variable Documentation

◆ k_mg_tag

const char k_mg_tag[] = "mg_reader"

static

Log tag for the reader's null-pointer guards.

Definition at line 33 of file mg_reader.c.

Referenced by mg_reader_check_geometry(), mg_reader_check_ptrs(), mg_reader_prefetch(), mg_reader_render(), mg_reader_status(), and mg_tile_decode().

Enumerations

Functions

Variables

Detailed Description

Enumeration Type Documentation

◆ mg_bits_t

◆ mg_color_t

◆ mg_fnv_t

◆ mg_metric_t

◆ mg_pixfmt_t

Function Documentation

◆ mg_append_str()

◆ mg_append_uint()

◆ mg_blit_tile()

◆ mg_clamp()

◆ mg_content_h()

◆ mg_fit_factor()

◆ mg_fnv1a()

◆ mg_g565()

◆ mg_map()

◆ mg_offsets()

◆ mg_pan()

◆ mg_pan_dir()

◆ mg_reader_bind()

◆ mg_reader_check_geometry()

◆ mg_reader_check_ptrs()

◆ mg_reader_init()

◆ mg_reader_prefetch()

◆ mg_reader_render()

◆ mg_reader_status()

◆ mg_reader_tap()

◆ mg_reader_toggle_zoom()

◆ mg_region()

◆ mg_render_minimap()

◆ mg_render_page()

◆ mg_render_status()

◆ mg_scale()

◆ mg_tile_decode()

◆ mg_tiles_of_region()

◆ mg_zone_hit()

Variable Documentation

◆ k_mg_tag