mipmap_cache.h

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/*
    This file is part of darktable,
    Copyright (C) 2011-2021 darktable developers.
 
    darktable is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    darktable is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with darktable.  If not, see <http://www.gnu.org/licenses/>.
*/
 
#pragma once
 
#include "common/cache.h"
#include "common/colorspaces.h"
#include "common/image.h"
 
#ifdef __cplusplus
extern "C" {
#endif
 
// sizes stored in the mipmap cache, set to fixed values in mipmap_cache.c
typedef enum dt_mipmap_size_t {
  DT_MIPMAP_0,               // 360x225 px
  DT_MIPMAP_1,               // 720x450 px
  DT_MIPMAP_2,               // 1440x900 px
  DT_MIPMAP_3,               // Full HD 1080p
  DT_MIPMAP_4,               // 2560x1440 px
  DT_MIPMAP_5,               // 4K/UHD -
  DT_MIPMAP_6,               // 5K
  DT_MIPMAP_7,               // 6K
  DT_MIPMAP_8,               // 8K
  DT_MIPMAP_F,               // unprocessed input float image downscaled to 720x450 or 1440x900 px for performance
  DT_MIPMAP_FULL,            // unprocessed input float image at original resolation
  DT_MIPMAP_NONE
} dt_mipmap_size_t;
 
// type to be passed to getter functions
typedef enum dt_mipmap_get_flags_t
{
  // only return when the requested buffer is loaded.
  // blocks until that happens.
  DT_MIPMAP_BLOCKING = 0,
  // don't actually acquire the lock if it is not
  // in cache (i.e. would have to be loaded first)
  DT_MIPMAP_TESTLOCK = 1
} dt_mipmap_get_flags_t;
 
// struct to be alloc'ed by the client, filled by dt_mipmap_cache_get()
typedef struct dt_mipmap_buffer_t
{
  dt_mipmap_size_t size;
  int32_t imgid;
  int32_t width, height;
  float iscale;
  uint8_t *buf;
  dt_colorspaces_color_profile_type_t color_space;
  dt_cache_entry_t *cache_entry;
} dt_mipmap_buffer_t;
 
typedef struct dt_mipmap_cache_one_t
{
  // one cache per mipmap scale!
  dt_cache_t cache;
 
  // a few stats on usage in this run.
  // long int to give 32-bits on old archs, so __sync* calls will work.
  long int stats_requests;   // number of total requests
  long int stats_near_match; // served with smaller mip res
  long int stats_misses;     // nothing returned at all.
  long int stats_fetches;    // texture was fetched (either as a stand-in or as per request)
  long int stats_standin;    // texture used as stand-in
} dt_mipmap_cache_one_t;
 
typedef struct dt_mipmap_cache_t
{
  // real width and height are stored per element
  // (could be smaller than the max for this mip level,
  // due to aspect ratio)
  size_t max_width[DT_MIPMAP_NONE], max_height[DT_MIPMAP_NONE];
  // size of an element inside buf
  size_t buffer_size[DT_MIPMAP_NONE];
 
  // one cache per mipmap level
  dt_mipmap_cache_one_t mip_thumbs;
  dt_mipmap_cache_one_t mip_f;
  dt_mipmap_cache_one_t mip_full;
  char cachedir[PATH_MAX]; // cached sha1sum filename for faster access
} dt_mipmap_cache_t;
 
// dynamic memory allocation interface for imageio backend: a write locked
// mipmap buffer is passed in, it might already contain a valid buffer. this
// function takes care of re-allocating, if necessary.
void *dt_mipmap_cache_alloc(dt_mipmap_buffer_t *buf, const dt_image_t *img);
 
void dt_mipmap_cache_init(dt_mipmap_cache_t *cache);
void dt_mipmap_cache_cleanup(dt_mipmap_cache_t *cache);
void dt_mipmap_cache_print(dt_mipmap_cache_t *cache);
 
// get a buffer and lock according to mode ('r' or 'w').
// see dt_mipmap_get_flags_t for explanation of the exact
// behaviour. pass 0 as flags for the default (best effort)
#define dt_mipmap_cache_get(A,B,C,D,E,F) dt_mipmap_cache_get_with_caller(A,B,C,D,E,F,__FILE__,__LINE__)
void dt_mipmap_cache_get_with_caller(
    dt_mipmap_cache_t *cache,
    dt_mipmap_buffer_t *buf,
    const int32_t imgid,
    const dt_mipmap_size_t mip,
    const dt_mipmap_get_flags_t flags,
    const char mode,
    const char *file,
    int line);
 
// convenience function with fewer params
#define dt_mipmap_cache_write_get(A,B,C,D) dt_mipmap_cache_write_get_with_caller(A,B,C,D,__FILE__,__LINE__)
void dt_mipmap_cache_write_get_with_caller(
    dt_mipmap_cache_t *cache,
    dt_mipmap_buffer_t *buf,
    const int32_t imgid,
    const int mip,
    const char *file,
    int line);
 
// drop a lock
#define dt_mipmap_cache_release(A, B) dt_mipmap_cache_release_with_caller(A, B, __FILE__, __LINE__)
void dt_mipmap_cache_release_with_caller(dt_mipmap_cache_t *cache, dt_mipmap_buffer_t *buf, const char *file,
                                         int line);
 
// remove thumbnails, so they will be regenerated:
void dt_mipmap_cache_remove(dt_mipmap_cache_t *cache, const int32_t imgid, const gboolean flush_disk);
void dt_mipmap_cache_remove_at_size(dt_mipmap_cache_t *cache, const int32_t imgid, const dt_mipmap_size_t mip, const gboolean flush_disk);
 
// evict thumbnails from cache. They will be written to disc if not existing
void dt_mimap_cache_evict(dt_mipmap_cache_t *cache, const int32_t imgid);
 
// return the closest mipmap size
// for the given window you wish to draw.
// a dt_mipmap_size_t has always a fixed resolution associated with it,
// depending on the user parameter for the maximum thumbnail dimensions.
// actual resolution depends on the image and is only known after
// the thumbnail is loaded.
dt_mipmap_size_t dt_mipmap_cache_get_matching_size(
    const dt_mipmap_cache_t *cache,
    const int32_t width,
    const int32_t height);
 
// copy over thumbnails. used by file operation that copies raw files, to speed up thumbnail generation.
// only copies over the jpg backend on disk, doesn't directly affect the in-memory cache.
void dt_mipmap_cache_copy_thumbnails(const dt_mipmap_cache_t *cache, const uint32_t dst_imgid, const uint32_t src_imgid);
 
#ifdef __cplusplus
}
#endif
 
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