fiv/fiv-thumbnail.c

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//
// fiv-thumbnail.c: thumbnail management
//
// Copyright (c) 2021, Přemysl Eric Janouch <p@janouch.name>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
//
#include <spng.h>
#include <webp/encode.h>
#include <webp/mux.h>
#include <glib/gstdio.h>
#include <math.h>
#include <stdbool.h>
#include "fiv-io.h"
#include "fiv-thumbnail.h"
#include "xdg.h"
#ifndef __linux__
#define st_mtim st_mtimespec
#endif // ! __linux__
// TODO(p): Consider merging back with fiv-io.
#define FIV_THUMBNAIL_ERROR fiv_thumbnail_error_quark()
G_DEFINE_QUARK(fiv-thumbnail-error-quark, fiv_thumbnail_error)
enum FivThumbnailError {
FIV_THUMBNAIL_ERROR_IO
};
static void
set_error(GError **error, const char *message)
{
g_set_error_literal(
error, FIV_THUMBNAIL_ERROR, FIV_THUMBNAIL_ERROR_IO, message);
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
GType
fiv_thumbnail_size_get_type(void)
{
static gsize guard;
if (g_once_init_enter(&guard)) {
#define XX(name, value, dir) {FIV_THUMBNAIL_SIZE_ ## name, \
"FIV_THUMBNAIL_SIZE_" #name, #name},
static const GEnumValue values[] = {FIV_THUMBNAIL_SIZES(XX) {}};
#undef XX
GType type = g_enum_register_static(
g_intern_static_string("FivThumbnailSize"), values);
g_once_init_leave(&guard, type);
}
return guard;
}
#define XX(name, value, dir) {value, dir},
FivThumbnailSizeInfo
fiv_thumbnail_sizes[FIV_THUMBNAIL_SIZE_COUNT] = {
FIV_THUMBNAIL_SIZES(XX)};
#undef XX
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
cairo_user_data_key_t fiv_thumbnail_key_lq;
static void
mark_thumbnail_lq(cairo_surface_t *surface)
{
cairo_surface_set_user_data(
surface, &fiv_thumbnail_key_lq, (void *) (intptr_t) 1, NULL);
}
gchar *
fiv_thumbnail_get_root(void)
{
gchar *cache_dir = get_xdg_home_dir("XDG_CACHE_HOME", ".cache");
gchar *thumbnails_dir = g_build_filename(cache_dir, "thumbnails", NULL);
g_free(cache_dir);
return thumbnails_dir;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// In principle similar to rescale_thumbnail() from fiv-browser.c.
static cairo_surface_t *
adjust_thumbnail(cairo_surface_t *thumbnail, double row_height)
{
cairo_format_t format = cairo_image_surface_get_format(thumbnail);
int w = 0, width = cairo_image_surface_get_width(thumbnail);
int h = 0, height = cairo_image_surface_get_height(thumbnail);
// Hardcode orientation.
FivIoOrientation orientation = (uintptr_t) cairo_surface_get_user_data(
thumbnail, &fiv_io_key_orientation);
cairo_matrix_t matrix = fiv_io_orientation_is_sideways(orientation)
? fiv_io_orientation_matrix(orientation, (w = height), (h = width))
: fiv_io_orientation_matrix(orientation, (w = width), (h = height));
double scale_x = 1;
double scale_y = 1;
if (w > FIV_THUMBNAIL_WIDE_COEFFICIENT * h) {
scale_x = FIV_THUMBNAIL_WIDE_COEFFICIENT * row_height / w;
scale_y = round(scale_x * h) / h;
} else {
scale_y = row_height / h;
scale_x = round(scale_y * w) / w;
}
if (orientation <= FivIoOrientation0 && scale_x == 1 && scale_y == 1)
return cairo_surface_reference(thumbnail);
int projected_width = round(scale_x * w);
int projected_height = round(scale_y * h);
cairo_surface_t *scaled = cairo_image_surface_create(
(format == CAIRO_FORMAT_RGB24 || format == CAIRO_FORMAT_RGB30)
? CAIRO_FORMAT_RGB24
: CAIRO_FORMAT_ARGB32,
projected_width, projected_height);
cairo_t *cr = cairo_create(scaled);
cairo_scale(cr, scale_x, scale_y);
cairo_set_source_surface(cr, thumbnail, 0, 0);
cairo_pattern_t *pattern = cairo_get_source(cr);
// CAIRO_FILTER_BEST, for some reason, works bad with CAIRO_FORMAT_RGB30.
cairo_pattern_set_filter(pattern, CAIRO_FILTER_GOOD);
cairo_pattern_set_extend(pattern, CAIRO_EXTEND_PAD);
cairo_pattern_set_matrix(pattern, &matrix);
cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
cairo_paint(cr);
cairo_destroy(cr);
return scaled;
}
static WebPData
encode_thumbnail(cairo_surface_t *surface)
{
WebPData bitstream = {};
WebPConfig config = {};
if (!WebPConfigInit(&config) || !WebPConfigLosslessPreset(&config, 6))
return bitstream;
config.near_lossless = 95;
config.thread_level = true;
if (!WebPValidateConfig(&config))
return bitstream;
bitstream.bytes = fiv_io_encode_webp(surface, &config, &bitstream.size);
return bitstream;
}
static void
save_thumbnail(cairo_surface_t *thumbnail, const char *path, GString *thum)
{
WebPMux *mux = WebPMuxNew();
WebPData bitstream = encode_thumbnail(thumbnail);
gboolean ok = WebPMuxSetImage(mux, &bitstream, true) == WEBP_MUX_OK;
WebPDataClear(&bitstream);
WebPData data = {.bytes = (const uint8_t *) thum->str, .size = thum->len};
ok = ok && WebPMuxSetChunk(mux, "THUM", &data, false) == WEBP_MUX_OK;
WebPData assembled = {};
WebPDataInit(&assembled);
ok = ok && WebPMuxAssemble(mux, &assembled) == WEBP_MUX_OK;
WebPMuxDelete(mux);
if (!ok) {
g_warning("thumbnail encoding failed");
return;
}
GError *e = NULL;
while (!g_file_set_contents(
path, (const gchar *) assembled.bytes, assembled.size, &e)) {
bool missing_parents =
e->domain == G_FILE_ERROR && e->code == G_FILE_ERROR_NOENT;
g_debug("%s: %s", path, e->message);
g_clear_error(&e);
if (!missing_parents)
break;
gchar *dirname = g_path_get_dirname(path);
int err = g_mkdir_with_parents(dirname, 0755);
if (err)
g_debug("%s: %s", dirname, g_strerror(errno));
g_free(dirname);
if (err)
break;
}
// It would be possible to create square thumbnails as well,
// but it seems like wasted effort.
WebPDataClear(&assembled);
}
gboolean
fiv_thumbnail_produce(GFile *target, FivThumbnailSize max_size, GError **error)
{
g_return_val_if_fail(max_size >= FIV_THUMBNAIL_SIZE_MIN &&
max_size <= FIV_THUMBNAIL_SIZE_MAX, FALSE);
// Local files only, at least for now.
gchar *path = g_file_get_path(target);
if (!path)
return FALSE;
GMappedFile *mf = g_mapped_file_new(path, FALSE, error);
if (!mf) {
g_free(path);
return FALSE;
}
GStatBuf st = {};
if (g_stat(path, &st)) {
set_error(error, g_strerror(errno));
g_free(path);
return FALSE;
}
// TODO(p): Add a flag to avoid loading all pages and frames.
FivIoProfile sRGB = fiv_io_profile_new_sRGB();
gsize filesize = g_mapped_file_get_length(mf);
cairo_surface_t *surface = fiv_io_open_from_data(
g_mapped_file_get_contents(mf), filesize, path, sRGB, FALSE, error);
g_free(path);
g_mapped_file_unref(mf);
if (sRGB)
fiv_io_profile_free(sRGB);
if (!surface)
return FALSE;
// Boilerplate copied from fiv_thumbnail_lookup().
gchar *uri = g_file_get_uri(target);
gchar *sum = g_compute_checksum_for_string(G_CHECKSUM_MD5, uri, -1);
gchar *thumbnails_dir = fiv_thumbnail_get_root();
GString *thum = g_string_new("");
g_string_append_printf(
thum, "%s%c%s%c", "Thumb::URI", 0, uri, 0);
g_string_append_printf(
thum, "%s%c%ld%c", "Thumb::Mtime", 0, (long) st.st_mtim.tv_sec, 0);
g_string_append_printf(
thum, "%s%c%ld%c", "Thumb::Size", 0, (long) filesize, 0);
g_string_append_printf(thum, "%s%c%d%c", "Thumb::Image::Width", 0,
cairo_image_surface_get_width(surface), 0);
g_string_append_printf(thum, "%s%c%d%c", "Thumb::Image::Height", 0,
cairo_image_surface_get_height(surface), 0);
// Without a CMM, no conversion is attempted.
if (sRGB) {
g_string_append_printf(
thum, "%s%c%s%c", "Thumb::ColorSpace", 0, "sRGB", 0);
}
for (int use = max_size; use >= FIV_THUMBNAIL_SIZE_MIN; use--) {
cairo_surface_t *scaled =
adjust_thumbnail(surface, fiv_thumbnail_sizes[use].size);
gchar *path = g_strdup_printf("%s/wide-%s/%s.webp", thumbnails_dir,
fiv_thumbnail_sizes[use].thumbnail_spec_name, sum);
save_thumbnail(scaled, path, thum);
cairo_surface_destroy(scaled);
g_free(path);
}
g_string_free(thum, TRUE);
g_free(thumbnails_dir);
g_free(sum);
g_free(uri);
cairo_surface_destroy(surface);
return TRUE;
}
static cairo_surface_t *
read_wide_thumbnail(
const gchar *path, const gchar *uri, time_t mtime, GError **error)
{
// TODO(p): Validate fiv_io_key_thum.
(void) uri;
(void) mtime;
return fiv_io_open(path, NULL, FALSE, error);
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
static int // tri-state
check_spng_thumbnail_texts(struct spng_text *texts, uint32_t texts_len,
const gchar *target, time_t mtime)
{
// May contain Thumb::Image::Width Thumb::Image::Height,
// but those aren't interesting currently (would be for fast previews).
bool need_uri = true, need_mtime = true;
for (uint32_t i = 0; i < texts_len; i++) {
struct spng_text *text = texts + i;
if (!strcmp(text->keyword, "Thumb::URI")) {
need_uri = false;
if (strcmp(target, text->text))
return false;
}
if (!strcmp(text->keyword, "Thumb::MTime")) {
need_mtime = false;
if (atol(text->text) != mtime)
return false;
}
}
return need_uri || need_mtime ? -1 : true;
}
static int // tri-state
check_spng_thumbnail(spng_ctx *ctx, const gchar *target, time_t mtime, int *err)
{
uint32_t texts_len = 0;
if ((*err = spng_get_text(ctx, NULL, &texts_len)))
return false;
int result = false;
struct spng_text *texts = g_malloc0_n(texts_len, sizeof *texts);
if (!(*err = spng_get_text(ctx, texts, &texts_len)))
result = check_spng_thumbnail_texts(texts, texts_len, target, mtime);
g_free(texts);
return result;
}
static cairo_surface_t *
read_spng_thumbnail(
const gchar *path, const gchar *uri, time_t mtime, GError **error)
{
FILE *fp;
cairo_surface_t *result = NULL;
if (!(fp = fopen(path, "rb"))) {
set_error(error, g_strerror(errno));
return NULL;
}
errno = 0;
spng_ctx *ctx = spng_ctx_new(0);
if (!ctx) {
set_error(error, g_strerror(errno));
goto fail_init;
}
int err;
size_t size = 0;
if ((err = spng_set_png_file(ctx, fp)) ||
(err = spng_set_image_limits(ctx, INT16_MAX, INT16_MAX)) ||
(err = spng_decoded_image_size(ctx, SPNG_FMT_RGBA8, &size))) {
set_error(error, spng_strerror(err));
goto fail;
}
if (check_spng_thumbnail(ctx, uri, mtime, &err) == false) {
set_error(error, err ? spng_strerror(err) : "mismatch");
goto fail;
}
struct spng_ihdr ihdr = {};
struct spng_trns trns = {};
spng_get_ihdr(ctx, &ihdr);
bool may_be_translucent = !spng_get_trns(ctx, &trns) ||
ihdr.color_type == SPNG_COLOR_TYPE_GRAYSCALE_ALPHA ||
ihdr.color_type == SPNG_COLOR_TYPE_TRUECOLOR_ALPHA;
cairo_surface_t *surface = cairo_image_surface_create(
may_be_translucent ? CAIRO_FORMAT_ARGB32 : CAIRO_FORMAT_RGB24,
ihdr.width, ihdr.height);
cairo_status_t surface_status = cairo_surface_status(surface);
if (surface_status != CAIRO_STATUS_SUCCESS) {
set_error(error, cairo_status_to_string(surface_status));
goto fail_data;
}
uint32_t *data = (uint32_t *) cairo_image_surface_get_data(surface);
g_assert((size_t) cairo_image_surface_get_stride(surface) *
cairo_image_surface_get_height(surface) == size);
cairo_surface_flush(surface);
if ((err = spng_decode_image(ctx, data, size, SPNG_FMT_RGBA8,
SPNG_DECODE_TRNS | SPNG_DECODE_GAMMA))) {
set_error(error, spng_strerror(err));
goto fail_data;
}
// The specification does not say where the required metadata should be,
// it could very well be broken up into two parts.
if (check_spng_thumbnail(ctx, uri, mtime, &err) != true) {
set_error(
error, err ? spng_strerror(err) : "mismatch or not a thumbnail");
goto fail_data;
}
// pixman can be mildly abused to do this operation, but it won't be faster.
if (may_be_translucent) {
for (size_t i = size / sizeof *data; i--; ) {
const uint8_t *unit = (const uint8_t *) &data[i];
uint32_t a = unit[3],
b = PREMULTIPLY8(a, unit[2]),
g = PREMULTIPLY8(a, unit[1]),
r = PREMULTIPLY8(a, unit[0]);
data[i] = a << 24 | r << 16 | g << 8 | b;
}
} else {
for (size_t i = size / sizeof *data; i--; ) {
uint32_t rgba = g_ntohl(data[i]);
data[i] = rgba << 24 | rgba >> 8;
}
}
cairo_surface_mark_dirty((result = surface));
fail_data:
if (!result)
cairo_surface_destroy(surface);
fail:
spng_ctx_free(ctx);
fail_init:
fclose(fp);
return result;
}
cairo_surface_t *
fiv_thumbnail_lookup(GFile *target, FivThumbnailSize size)
{
g_return_val_if_fail(size >= FIV_THUMBNAIL_SIZE_MIN &&
size <= FIV_THUMBNAIL_SIZE_MAX, NULL);
// Local files only, at least for now.
gchar *path = g_file_get_path(target);
if (!path)
return NULL;
GStatBuf st = {};
int err = g_stat(path, &st);
g_free(path);
if (err)
return NULL;
gchar *uri = g_file_get_uri(target);
gchar *sum = g_compute_checksum_for_string(G_CHECKSUM_MD5, uri, -1);
gchar *thumbnails_dir = fiv_thumbnail_get_root();
// The lookup sequence is: nominal..max, then mirroring back to ..min.
cairo_surface_t *result = NULL;
GError *error = NULL;
for (int i = 0; i < FIV_THUMBNAIL_SIZE_COUNT; i++) {
FivThumbnailSize use = size + i;
if (use > FIV_THUMBNAIL_SIZE_MAX)
use = FIV_THUMBNAIL_SIZE_MAX - i;
const char *name = fiv_thumbnail_sizes[use].thumbnail_spec_name;
gchar *wide =
g_strdup_printf("%s/wide-%s/%s.webp", thumbnails_dir, name, sum);
result = read_wide_thumbnail(wide, uri, st.st_mtim.tv_sec, &error);
if (error) {
g_debug("%s: %s", wide, error->message);
g_clear_error(&error);
}
g_free(wide);
if (result) {
// Higher up we can't distinguish images smaller than the thumbnail.
// Also, try not to rescale the already rescaled.
if (use != size)
mark_thumbnail_lq(result);
break;
}
gchar *path =
g_strdup_printf("%s/%s/%s.png", thumbnails_dir, name, sum);
result = read_spng_thumbnail(path, uri, st.st_mtim.tv_sec, &error);
if (error) {
g_debug("%s: %s", path, error->message);
g_clear_error(&error);
}
g_free(path);
if (result) {
// Whatever produced it, we may be able to outclass it.
mark_thumbnail_lq(result);
break;
}
}
// TODO(p): We can definitely extract embedded thumbnails, but it should be
// done as a separate stage--the file may be stored on a slow device.
g_free(thumbnails_dir);
g_free(sum);
g_free(uri);
return result;
}