feat(tiny_ttf): backport Tiny TTF to lvgl 8 (#4727)

Kconfig

@@ -1011,6 +1011,13 @@ menu "LVGL configuration"
             endmenu
         endif
 
+        config LV_USE_TINY_TTF
+            bool "Tiny TTF library"
+        config LV_TINY_TTF_FILE_SUPPORT
+            bool "Load TTF data from files"
+            depends on LV_USE_TINY_TTF
+            default n
+
         config LV_USE_RLOTTIE
             bool "Lottie library"
 

docs/libs/index.md

@@ -12,6 +12,7 @@
    png
    gif
    freetype
+   tiny_ttf
    qrcode
    rlottie
    ffmpeg

docs/libs/tiny_ttf.md

@@ -0,0 +1,35 @@
+# Tiny TTF font engine
+
+## Usage
+
+Use https://github.com/nothings/stb to render TrueType fonts in LVGL.
+
+When enabled in `lv_conf.h` with `LV_USE_TINY_TTF`
+`lv_tiny_ttf_create_data(data, data_size, font_size)` can be used to
+create a TTF font instance at the specified font size. You can then
+use that font anywhere `lv_font_t` is accepted.
+
+By default, the TTF or OTF file must be embedded as an array, either in
+a header, or loaded into RAM in order to function.
+
+However, if `LV_TINY_TTF_FILE_SUPPORT` is enabled,
+`lv_tiny_ttf_create_file(path, font_size)` will also be available,
+allowing tiny_ttf to stream from a file. The file must remain open the
+entire time the font is being used, and streaming on demand may be
+considerably slower.
+
+After a font is created, you can change the font size in pixels by using
+`lv_tiny_ttf_set_size(font, font_size)`.
+
+By default, a font will use up to 4KB of cache to speed up rendering
+glyphs. This maximum can be changed by using
+`lv_tiny_ttf_create_data_ex(data, data_size, font_size, cache_size)`
+or `lv_tiny_ttf_create_file_ex(path, font_size, cache_size)` (when
+available). The cache size is indicated in bytes.
+
+## API
+
+```eval_rst
+.. doxygenfile:: lv_tiny_ttf.h
+  :project: lvgl
+```

lv_conf_template.h

@@ -679,6 +679,13 @@
     #endif
 #endif
 
+/*Tiny TTF library*/
+#define LV_USE_TINY_TTF 0
+#if LV_USE_TINY_TTF
+    /*Load TTF data from files*/
+    #define LV_TINY_TTF_FILE_SUPPORT 0
+#endif
+
 /*Rlottie library*/
 #define LV_USE_RLOTTIE 0
 

src/extra/libs/lv_libs.h

@@ -22,6 +22,7 @@ extern "C" {
 #include "freetype/lv_freetype.h"
 #include "rlottie/lv_rlottie.h"
 #include "ffmpeg/lv_ffmpeg.h"
+#include "tiny_ttf/lv_tiny_ttf.h"
 
 /*********************
  *      DEFINES

src/extra/libs/tiny_ttf/lv_tiny_ttf.c

@@ -0,0 +1,284 @@
+#include "lv_tiny_ttf.h"
+
+#if LV_USE_TINY_TTF
+#include <stdio.h>
+#include "../../../misc/lv_lru.h"
+
+#define STB_RECT_PACK_IMPLEMENTATION
+#define STBRP_STATIC
+#define STBTT_STATIC
+#define STB_TRUETYPE_IMPLEMENTATION
+#define STBTT_HEAP_FACTOR_SIZE_32 50
+#define STBTT_HEAP_FACTOR_SIZE_128 20
+#define STBTT_HEAP_FACTOR_SIZE_DEFAULT 10
+#define STBTT_malloc(x, u) ((void)(u), lv_mem_alloc(x))
+#define STBTT_free(x, u) ((void)(u), lv_mem_free(x))
+#define TTF_MALLOC(x) (lv_mem_alloc(x))
+#define TTF_FREE(x) (lv_mem_free(x))
+
+#if LV_TINY_TTF_FILE_SUPPORT
+/* a hydra stream that can be in memory or from a file*/
+typedef struct ttf_cb_stream {
+    lv_fs_file_t * file;
+    const void * data;
+    size_t size;
+    size_t position;
+} ttf_cb_stream_t;
+
+static void ttf_cb_stream_read(ttf_cb_stream_t * stream, void * data, size_t to_read)
+{
+    if(stream->file != NULL) {
+        uint32_t br;
+        lv_fs_read(stream->file, data, to_read, &br);
+    }
+    else {
+        if(to_read + stream->position >= stream->size) {
+            to_read = stream->size - stream->position;
+        }
+        lv_memcpy(data, ((const unsigned char *)stream->data + stream->position), to_read);
+        stream->position += to_read;
+    }
+}
+static void ttf_cb_stream_seek(ttf_cb_stream_t * stream, size_t position)
+{
+    if(stream->file != NULL) {
+        lv_fs_seek(stream->file, position, LV_FS_SEEK_SET);
+    }
+    else {
+        if(position > stream->size) {
+            stream->position = stream->size;
+        }
+        else {
+            stream->position = position;
+        }
+    }
+}
+
+/* for stream support */
+#define STBTT_STREAM_TYPE ttf_cb_stream_t *
+#define STBTT_STREAM_SEEK(s, x) ttf_cb_stream_seek(s, x);
+#define STBTT_STREAM_READ(s, x, y) ttf_cb_stream_read(s, x, y);
+#endif /*LV_TINY_TTF_FILE_SUPPORT*/
+
+#include "stb_rect_pack.h"
+#include "stb_truetype_htcw.h"
+
+typedef struct ttf_font_desc {
+    lv_fs_file_t file;
+#if LV_TINY_TTF_FILE_SUPPORT
+    ttf_cb_stream_t stream;
+#else
+    const uint8_t * stream;
+#endif
+    stbtt_fontinfo info;
+    float scale;
+    int ascent;
+    int descent;
+    lv_lru_t * bitmap_cache;
+} ttf_font_desc_t;
+
+typedef struct ttf_bitmap_cache_key {
+    uint32_t unicode_letter;
+    lv_coord_t line_height;
+} ttf_bitmap_cache_key_t;
+
+static bool ttf_get_glyph_dsc_cb(const lv_font_t * font, lv_font_glyph_dsc_t * dsc_out, uint32_t unicode_letter,
+                                 uint32_t unicode_letter_next)
+{
+    if(unicode_letter < 0x20 ||
+       unicode_letter == 0xf8ff || /*LV_SYMBOL_DUMMY*/
+       unicode_letter == 0x200c) { /*ZERO WIDTH NON-JOINER*/
+        dsc_out->box_w = 0;
+        dsc_out->adv_w = 0;
+        dsc_out->box_h = 0; /*height of the bitmap in [px]*/
+        dsc_out->ofs_x = 0; /*X offset of the bitmap in [pf]*/
+        dsc_out->ofs_y = 0; /*Y offset of the bitmap in [pf]*/
+        dsc_out->bpp = 0;
+        dsc_out->is_placeholder = false;
+        return true;
+    }
+    ttf_font_desc_t * dsc = (ttf_font_desc_t *)font->dsc;
+    int g1 = stbtt_FindGlyphIndex(&dsc->info, (int)unicode_letter);
+    if(g1 == 0) {
+        /* Glyph not found */
+        return false;
+    }
+    int x1, y1, x2, y2;
+
+    stbtt_GetGlyphBitmapBox(&dsc->info, g1, dsc->scale, dsc->scale, &x1, &y1, &x2, &y2);
+    int g2 = 0;
+    if(unicode_letter_next != 0) {
+        g2 = stbtt_FindGlyphIndex(&dsc->info, (int)unicode_letter_next);
+    }
+    int advw, lsb;
+    stbtt_GetGlyphHMetrics(&dsc->info, g1, &advw, &lsb);
+    int k = stbtt_GetGlyphKernAdvance(&dsc->info, g1, g2);
+    dsc_out->adv_w = (uint16_t)floor((((float)advw + (float)k) * dsc->scale) +
+                                     0.5f); /*Horizontal space required by the glyph in [px]*/
+
+    dsc_out->adv_w = (uint16_t)floor((((float)advw + (float)k) * dsc->scale) +
+                                     0.5f); /*Horizontal space required by the glyph in [px]*/
+    dsc_out->box_w = (x2 - x1 + 1);         /*width of the bitmap in [px]*/
+    dsc_out->box_h = (y2 - y1 + 1);         /*height of the bitmap in [px]*/
+    dsc_out->ofs_x = x1;                    /*X offset of the bitmap in [pf]*/
+    dsc_out->ofs_y = -y2;                   /*Y offset of the bitmap measured from the as line*/
+    dsc_out->bpp = 8;                       /*Bits per pixel: 1/2/4/8*/
+    dsc_out->is_placeholder = false;
+    return true; /*true: glyph found; false: glyph was not found*/
+}
+
+static const uint8_t * ttf_get_glyph_bitmap_cb(const lv_font_t * font, uint32_t unicode_letter)
+{
+    ttf_font_desc_t * dsc = (ttf_font_desc_t *)font->dsc;
+    const stbtt_fontinfo * info = (const stbtt_fontinfo *)&dsc->info;
+    int g1 = stbtt_FindGlyphIndex(info, (int)unicode_letter);
+    if(g1 == 0) {
+        /* Glyph not found */
+        return NULL;
+    }
+    int x1, y1, x2, y2;
+    stbtt_GetGlyphBitmapBox(info, g1, dsc->scale, dsc->scale, &x1, &y1, &x2, &y2);
+    int w, h;
+    w = x2 - x1 + 1;
+    h = y2 - y1 + 1;
+    uint32_t stride = w;
+    /*Try to load from cache*/
+    ttf_bitmap_cache_key_t cache_key;
+    lv_memset(&cache_key, 0, sizeof(cache_key)); /*Zero padding*/
+    cache_key.unicode_letter = unicode_letter;
+    cache_key.line_height = font->line_height;
+    uint8_t * buffer = NULL;
+    lv_lru_get(dsc->bitmap_cache, &cache_key, sizeof(cache_key), (void **)&buffer);
+    if(buffer) {
+        return buffer;
+    }
+    LV_LOG_TRACE("cache miss for letter: %u", unicode_letter);
+    /*Prepare space in cache*/
+    size_t szb = h * stride;
+    buffer = lv_mem_alloc(szb);
+    if(!buffer) {
+        LV_LOG_ERROR("failed to allocate cache value");
+        return NULL;
+    }
+    lv_memset(buffer, 0, szb);
+    if(LV_LRU_OK != lv_lru_set(dsc->bitmap_cache, &cache_key, sizeof(cache_key), buffer, szb)) {
+        LV_LOG_ERROR("failed to add cache value");
+        lv_mem_free(buffer);
+        return NULL;
+    }
+    /*Render into cache*/
+    stbtt_MakeGlyphBitmap(info, buffer, w, h, stride, dsc->scale, dsc->scale, g1);
+    return buffer;
+}
+
+static lv_font_t * lv_tiny_ttf_create(const char * path, const void * data, size_t data_size, lv_coord_t font_size,
+                                      size_t cache_size)
+{
+    if((path == NULL && data == NULL) || 0 >= font_size) {
+        LV_LOG_ERROR("tiny_ttf: invalid argument\n");
+        return NULL;
+    }
+    ttf_font_desc_t * dsc = (ttf_font_desc_t *)TTF_MALLOC(sizeof(ttf_font_desc_t));
+    if(dsc == NULL) {
+        LV_LOG_ERROR("tiny_ttf: out of memory\n");
+        return NULL;
+    }
+#if LV_TINY_TTF_FILE_SUPPORT
+    if(path != NULL) {
+        if(LV_FS_RES_OK != lv_fs_open(&dsc->file, path, LV_FS_MODE_RD)) {
+            LV_LOG_ERROR("tiny_ttf: unable to open %s\n", path);
+            goto err_after_dsc;
+        }
+        dsc->stream.file = &dsc->file;
+    }
+    else {
+        dsc->stream.file = NULL;
+        dsc->stream.data = (const uint8_t *)data;
+        dsc->stream.size = data_size;
+        dsc->stream.position = 0;
+    }
+    if(0 == stbtt_InitFont(&dsc->info, &dsc->stream, stbtt_GetFontOffsetForIndex(&dsc->stream, 0))) {
+        LV_LOG_ERROR("tiny_ttf: init failed\n");
+        goto err_after_dsc;
+    }
+
+#else
+    dsc->stream = (const uint8_t *)data;
+    LV_UNUSED(data_size);
+    if(0 == stbtt_InitFont(&dsc->info, dsc->stream, stbtt_GetFontOffsetForIndex(dsc->stream, 0))) {
+        LV_LOG_ERROR("tiny_ttf: init failed\n");
+        goto err_after_dsc;
+    }
+#endif
+
+    dsc->bitmap_cache = lv_lru_create(cache_size, font_size * font_size, lv_mem_free, lv_mem_free);
+    if(dsc->bitmap_cache == NULL) {
+        LV_LOG_ERROR("failed to create lru cache");
+        goto err_after_dsc;
+    }
+
+    lv_font_t * out_font = (lv_font_t *)TTF_MALLOC(sizeof(lv_font_t));
+    if(out_font == NULL) {
+        LV_LOG_ERROR("tiny_ttf: out of memory\n");
+        goto err_after_bitmap_cache;
+    }
+    lv_memset(out_font, 0, sizeof(lv_font_t));
+    out_font->get_glyph_dsc = ttf_get_glyph_dsc_cb;
+    out_font->get_glyph_bitmap = ttf_get_glyph_bitmap_cb;
+    out_font->dsc = dsc;
+    lv_tiny_ttf_set_size(out_font, font_size);
+    return out_font;
+err_after_bitmap_cache:
+    lv_lru_del(dsc->bitmap_cache);
+err_after_dsc:
+    TTF_FREE(dsc);
+    return NULL;
+}
+#if LV_TINY_TTF_FILE_SUPPORT
+lv_font_t * lv_tiny_ttf_create_file_ex(const char * path, lv_coord_t font_size, size_t cache_size)
+{
+    return lv_tiny_ttf_create(path, NULL, 0, font_size, cache_size);
+}
+lv_font_t * lv_tiny_ttf_create_file(const char * path, lv_coord_t font_size)
+{
+    return lv_tiny_ttf_create_file_ex(path, font_size, 4096);
+}
+#endif /*LV_TINY_TTF_FILE_SUPPORT*/
+lv_font_t * lv_tiny_ttf_create_data_ex(const void * data, size_t data_size, lv_coord_t font_size, size_t cache_size)
+{
+    return lv_tiny_ttf_create(NULL, data, data_size, font_size, cache_size);
+}
+lv_font_t * lv_tiny_ttf_create_data(const void * data, size_t data_size, lv_coord_t font_size)
+{
+    return lv_tiny_ttf_create_data_ex(data, data_size, font_size, 4096);
+}
+void lv_tiny_ttf_set_size(lv_font_t * font, lv_coord_t font_size)
+{
+    if(font_size <= 0) {
+        LV_LOG_ERROR("invalid font size: %"PRIx32, font_size);
+        return;
+    }
+    ttf_font_desc_t * dsc = (ttf_font_desc_t *)font->dsc;
+    dsc->scale = stbtt_ScaleForMappingEmToPixels(&dsc->info, font_size);
+    int line_gap = 0;
+    stbtt_GetFontVMetrics(&dsc->info, &dsc->ascent, &dsc->descent, &line_gap);
+    font->line_height = (lv_coord_t)(dsc->scale * (dsc->ascent - dsc->descent + line_gap));
+    font->base_line = (lv_coord_t)(dsc->scale * (line_gap - dsc->descent));
+}
+void lv_tiny_ttf_destroy(lv_font_t * font)
+{
+    if(font != NULL) {
+        if(font->dsc != NULL) {
+            ttf_font_desc_t * ttf = (ttf_font_desc_t *)font->dsc;
+#if LV_TINY_TTF_FILE_SUPPORT
+            if(ttf->stream.file != NULL) {
+                lv_fs_close(&ttf->file);
+            }
+#endif
+            lv_lru_del(ttf->bitmap_cache);
+            TTF_FREE(ttf);
+        }
+        TTF_FREE(font);
+    }
+}
+#endif /*LV_USE_TINY_TTF*/

src/extra/libs/tiny_ttf/lv_tiny_ttf.h

@@ -0,0 +1,62 @@
+/**
+ * @file lv_tiny_ttf.h
+ *
+ */
+
+#ifndef LV_TINY_TTF_H
+#define LV_TINY_TTF_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*********************
+ *      INCLUDES
+ *********************/
+#include "../../../lvgl.h"
+
+#if LV_USE_TINY_TTF
+
+/*********************
+ *      DEFINES
+ *********************/
+
+/**********************
+ *      TYPEDEFS
+ **********************/
+
+/**********************
+ * GLOBAL PROTOTYPES
+ **********************/
+
+#if LV_TINY_TTF_FILE_SUPPORT
+/* create a font from the specified file or path with the specified line height.*/
+lv_font_t * lv_tiny_ttf_create_file(const char * path, lv_coord_t font_size);
+
+/* create a font from the specified file or path with the specified line height with the specified cache size.*/
+lv_font_t * lv_tiny_ttf_create_file_ex(const char * path, lv_coord_t font_size, size_t cache_size);
+#endif /*LV_TINY_TTF_FILE_SUPPORT*/
+
+/* create a font from the specified data pointer with the specified line height.*/
+lv_font_t * lv_tiny_ttf_create_data(const void * data, size_t data_size, lv_coord_t font_size);
+
+/* create a font from the specified data pointer with the specified line height and the specified cache size.*/
+lv_font_t * lv_tiny_ttf_create_data_ex(const void * data, size_t data_size, lv_coord_t font_size, size_t cache_size);
+
+/* set the size of the font to a new font_size*/
+void lv_tiny_ttf_set_size(lv_font_t * font, lv_coord_t font_size);
+
+/* destroy a font previously created with lv_tiny_ttf_create_xxxx()*/
+void lv_tiny_ttf_destroy(lv_font_t * font);
+
+/**********************
+ *      MACROS
+ **********************/
+
+#endif /*LV_USE_TINY_TTF*/
+
+#ifdef __cplusplus
+} /*extern "C"*/
+#endif
+
+#endif /*LV_TINY_TTF_H*/

src/extra/libs/tiny_ttf/stb_rect_pack.h

@@ -0,0 +1,637 @@
+// stb_rect_pack.h - v1.01 - public domain - rectangle packing
+// Sean Barrett 2014
+//
+// Useful for e.g. packing rectangular textures into an atlas.
+// Does not do rotation.
+//
+// Before #including,
+//
+//    #define STB_RECT_PACK_IMPLEMENTATION
+//
+// in the file that you want to have the implementation.
+//
+// Not necessarily the awesomest packing method, but better than
+// the totally naive one in stb_truetype (which is primarily what
+// this is meant to replace).
+//
+// Has only had a few tests run, may have issues.
+//
+// More docs to come.
+//
+// No memory allocations; uses qsort() and assert() from stdlib.
+// Can override those by defining STBRP_SORT and STBRP_ASSERT.
+//
+// This library currently uses the Skyline Bottom-Left algorithm.
+//
+// Please note: better rectangle packers are welcome! Please
+// implement them to the same API, but with a different init
+// function.
+//
+// Credits
+//
+//  Library
+//    Sean Barrett
+//  Minor features
+//    Martins Mozeiko
+//    github:IntellectualKitty
+//
+//  Bugfixes / warning fixes
+//    Jeremy Jaussaud
+//    Fabian Giesen
+//
+// Version history:
+//
+//     1.01  (2021-07-11)  always use large rect mode, expose STBRP__MAXVAL in public section
+//     1.00  (2019-02-25)  avoid small space waste; gracefully fail too-wide rectangles
+//     0.99  (2019-02-07)  warning fixes
+//     0.11  (2017-03-03)  return packing success/fail result
+//     0.10  (2016-10-25)  remove cast-away-const to avoid warnings
+//     0.09  (2016-08-27)  fix compiler warnings
+//     0.08  (2015-09-13)  really fix bug with empty rects (w=0 or h=0)
+//     0.07  (2015-09-13)  fix bug with empty rects (w=0 or h=0)
+//     0.06  (2015-04-15)  added STBRP_SORT to allow replacing qsort
+//     0.05:  added STBRP_ASSERT to allow replacing assert
+//     0.04:  fixed minor bug in STBRP_LARGE_RECTS support
+//     0.01:  initial release
+//
+// LICENSE
+//
+//   See end of file for license information.
+
+//////////////////////////////////////////////////////////////////////////////
+//
+//       INCLUDE SECTION
+//
+
+#ifndef STB_INCLUDE_STB_RECT_PACK_H
+#define STB_INCLUDE_STB_RECT_PACK_H
+
+#define STB_RECT_PACK_VERSION  1
+
+#ifdef STBRP_STATIC
+    #define STBRP_DEF static
+#else
+    #define STBRP_DEF extern
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/// @cond
+/**
+ *  Tells Doxygen to ignore a duplicate declaration
+ */
+typedef struct stbrp_context stbrp_context;
+typedef struct stbrp_node    stbrp_node;
+typedef struct stbrp_rect    stbrp_rect;
+/// @endcond
+
+typedef int            stbrp_coord;
+
+#define STBRP__MAXVAL  0x7fffffff
+// Mostly for internal use, but this is the maximum supported coordinate value.
+
+#if defined(__GNUC__) || defined(__clang__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-function"
+#endif
+
+
+STBRP_DEF int stbrp_pack_rects(stbrp_context * context, stbrp_rect * rects, int num_rects);
+// Assign packed locations to rectangles. The rectangles are of type
+// 'stbrp_rect' defined below, stored in the array 'rects', and there
+// are 'num_rects' many of them.
+//
+// Rectangles which are successfully packed have the 'was_packed' flag
+// set to a non-zero value and 'x' and 'y' store the minimum location
+// on each axis (i.e. bottom-left in cartesian coordinates, top-left
+// if you imagine y increasing downwards). Rectangles which do not fit
+// have the 'was_packed' flag set to 0.
+//
+// You should not try to access the 'rects' array from another thread
+// while this function is running, as the function temporarily reorders
+// the array while it executes.
+//
+// To pack into another rectangle, you need to call stbrp_init_target
+// again. To continue packing into the same rectangle, you can call
+// this function again. Calling this multiple times with multiple rect
+// arrays will probably produce worse packing results than calling it
+// a single time with the full rectangle array, but the option is
+// available.
+//
+// The function returns 1 if all of the rectangles were successfully
+// packed and 0 otherwise.
+
+struct stbrp_rect {
+    // reserved for your use:
+    int            id;
+
+    // input:
+    stbrp_coord    w, h;
+
+    // output:
+    stbrp_coord    x, y;
+    int            was_packed;  // non-zero if valid packing
+
+}; // 16 bytes, nominally
+
+
+STBRP_DEF void stbrp_init_target(stbrp_context * context, int width, int height, stbrp_node * nodes, int num_nodes);
+// Initialize a rectangle packer to:
+//    pack a rectangle that is 'width' by 'height' in dimensions
+//    using temporary storage provided by the array 'nodes', which is 'num_nodes' long
+//
+// You must call this function every time you start packing into a new target.
+//
+// There is no "shutdown" function. The 'nodes' memory must stay valid for
+// the following stbrp_pack_rects() call (or calls), but can be freed after
+// the call (or calls) finish.
+//
+// Note: to guarantee best results, either:
+//       1. make sure 'num_nodes' >= 'width'
+//   or  2. call stbrp_allow_out_of_mem() defined below with 'allow_out_of_mem = 1'
+//
+// If you don't do either of the above things, widths will be quantized to multiples
+// of small integers to guarantee the algorithm doesn't run out of temporary storage.
+//
+// If you do #2, then the non-quantized algorithm will be used, but the algorithm
+// may run out of temporary storage and be unable to pack some rectangles.
+
+STBRP_DEF void stbrp_setup_allow_out_of_mem(stbrp_context * context, int allow_out_of_mem);
+// Optionally call this function after init but before doing any packing to
+// change the handling of the out-of-temp-memory scenario, described above.
+// If you call init again, this will be reset to the default (false).
+
+
+STBRP_DEF void stbrp_setup_heuristic(stbrp_context * context, int heuristic);
+// Optionally select which packing heuristic the library should use. Different
+// heuristics will produce better/worse results for different data sets.
+// If you call init again, this will be reset to the default.
+
+enum {
+    STBRP_HEURISTIC_Skyline_default = 0,
+    STBRP_HEURISTIC_Skyline_BL_sortHeight = STBRP_HEURISTIC_Skyline_default,
+    STBRP_HEURISTIC_Skyline_BF_sortHeight
+};
+
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// the details of the following structures don't matter to you, but they must
+// be visible so you can handle the memory allocations for them
+
+struct stbrp_node {
+    stbrp_coord  x, y;
+    stbrp_node * next;
+};
+
+struct stbrp_context {
+    int width;
+    int height;
+    int align;
+    int init_mode;
+    int heuristic;
+    int num_nodes;
+    stbrp_node * active_head;
+    stbrp_node * free_head;
+    stbrp_node extra[2]; // we allocate two extra nodes so optimal user-node-count is 'width' not 'width+2'
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
+//////////////////////////////////////////////////////////////////////////////
+//
+//     IMPLEMENTATION SECTION
+//
+
+#ifdef STB_RECT_PACK_IMPLEMENTATION
+#ifndef STBRP_SORT
+    #include <stdlib.h>
+    #define STBRP_SORT qsort
+#endif
+
+#ifndef STBRP_ASSERT
+    #include <assert.h>
+    #define STBRP_ASSERT assert
+#endif
+
+#ifdef _MSC_VER
+    #define STBRP__NOTUSED(v)  (void)(v)
+    #define STBRP__CDECL       __cdecl
+#else
+    #define STBRP__NOTUSED(v)  (void)sizeof(v)
+    #define STBRP__CDECL
+#endif
+
+enum {
+    STBRP__INIT_skyline = 1
+};
+
+STBRP_DEF void stbrp_setup_heuristic(stbrp_context * context, int heuristic)
+{
+    switch(context->init_mode) {
+        case STBRP__INIT_skyline:
+            STBRP_ASSERT(heuristic == STBRP_HEURISTIC_Skyline_BL_sortHeight || heuristic == STBRP_HEURISTIC_Skyline_BF_sortHeight);
+            context->heuristic = heuristic;
+            break;
+        default:
+            STBRP_ASSERT(0);
+    }
+}
+
+STBRP_DEF void stbrp_setup_allow_out_of_mem(stbrp_context * context, int allow_out_of_mem)
+{
+    if(allow_out_of_mem)
+        // if it's ok to run out of memory, then don't bother aligning them;
+        // this gives better packing, but may fail due to OOM (even though
+        // the rectangles easily fit). @TODO a smarter approach would be to only
+        // quantize once we've hit OOM, then we could get rid of this parameter.
+        context->align = 1;
+    else {
+        // if it's not ok to run out of memory, then quantize the widths
+        // so that num_nodes is always enough nodes.
+        //
+        // I.e. num_nodes * align >= width
+        //                  align >= width / num_nodes
+        //                  align = ceil(width/num_nodes)
+
+        context->align = (context->width + context->num_nodes - 1) / context->num_nodes;
+    }
+}
+
+STBRP_DEF void stbrp_init_target(stbrp_context * context, int width, int height, stbrp_node * nodes, int num_nodes)
+{
+    int i;
+
+    for(i = 0; i < num_nodes - 1; ++i)
+        nodes[i].next = &nodes[i + 1];
+    nodes[i].next = NULL;
+    context->init_mode = STBRP__INIT_skyline;
+    context->heuristic = STBRP_HEURISTIC_Skyline_default;
+    context->free_head = &nodes[0];
+    context->active_head = &context->extra[0];
+    context->width = width;
+    context->height = height;
+    context->num_nodes = num_nodes;
+    stbrp_setup_allow_out_of_mem(context, 0);
+
+    // node 0 is the full width, node 1 is the sentinel (lets us not store width explicitly)
+    context->extra[0].x = 0;
+    context->extra[0].y = 0;
+    context->extra[0].next = &context->extra[1];
+    context->extra[1].x = (stbrp_coord) width;
+    context->extra[1].y = (1 << 30);
+    context->extra[1].next = NULL;
+}
+
+// find minimum y position if it starts at x1
+static int stbrp__skyline_find_min_y(stbrp_context * c, stbrp_node * first, int x0, int width, int * pwaste)
+{
+    stbrp_node * node = first;
+    int x1 = x0 + width;
+    int min_y, visited_width, waste_area;
+
+    STBRP__NOTUSED(c);
+
+    STBRP_ASSERT(first->x <= x0);
+
+#if 0
+    // skip in case we're past the node
+    while(node->next->x <= x0)
+        ++node;
+#else
+    STBRP_ASSERT(node->next->x > x0); // we ended up handling this in the caller for efficiency
+#endif
+
+    STBRP_ASSERT(node->x <= x0);
+
+    min_y = 0;
+    waste_area = 0;
+    visited_width = 0;
+    while(node->x < x1) {
+        if(node->y > min_y) {
+            // raise min_y higher.
+            // we've accounted for all waste up to min_y,
+            // but we'll now add more waste for everything we've visited
+            waste_area += visited_width * (node->y - min_y);
+            min_y = node->y;
+            // the first time through, visited_width might be reduced
+            if(node->x < x0)
+                visited_width += node->next->x - x0;
+            else
+                visited_width += node->next->x - node->x;
+        }
+        else {
+            // add waste area
+            int under_width = node->next->x - node->x;
+            if(under_width + visited_width > width)
+                under_width = width - visited_width;
+            waste_area += under_width * (min_y - node->y);
+            visited_width += under_width;
+        }
+        node = node->next;
+    }
+
+    *pwaste = waste_area;
+    return min_y;
+}
+
+typedef struct {
+    int x, y;
+    stbrp_node ** prev_link;
+} stbrp__findresult;
+
+static stbrp__findresult stbrp__skyline_find_best_pos(stbrp_context * c, int width, int height)
+{
+    int best_waste = (1 << 30), best_x, best_y = (1 << 30);
+    stbrp__findresult fr;
+    stbrp_node ** prev, * node, * tail, ** best = NULL;
+
+    // align to multiple of c->align
+    width = (width + c->align - 1);
+    width -= width % c->align;
+    STBRP_ASSERT(width % c->align == 0);
+
+    // if it can't possibly fit, bail immediately
+    if(width > c->width || height > c->height) {
+        fr.prev_link = NULL;
+        fr.x = fr.y = 0;
+        return fr;
+    }
+
+    node = c->active_head;
+    prev = &c->active_head;
+    while(node->x + width <= c->width) {
+        int y, waste;
+        y = stbrp__skyline_find_min_y(c, node, node->x, width, &waste);
+        if(c->heuristic == STBRP_HEURISTIC_Skyline_BL_sortHeight) {  // actually just want to test BL
+            // bottom left
+            if(y < best_y) {
+                best_y = y;
+                best = prev;
+            }
+        }
+        else {
+            // best-fit
+            if(y + height <= c->height) {
+                // can only use it if it first vertically
+                if(y < best_y || (y == best_y && waste < best_waste)) {
+                    best_y = y;
+                    best_waste = waste;
+                    best = prev;
+                }
+            }
+        }
+        prev = &node->next;
+        node = node->next;
+    }
+
+    best_x = (best == NULL) ? 0 : (*best)->x;
+
+    // if doing best-fit (BF), we also have to try aligning right edge to each node position
+    //
+    // e.g, if fitting
+    //
+    //     ____________________
+    //    |____________________|
+    //
+    //            into
+    //
+    //   |                         |
+    //   |             ____________|
+    //   |____________|
+    //
+    // then right-aligned reduces waste, but bottom-left BL is always chooses left-aligned
+    //
+    // This makes BF take about 2x the time
+
+    if(c->heuristic == STBRP_HEURISTIC_Skyline_BF_sortHeight) {
+        tail = c->active_head;
+        node = c->active_head;
+        prev = &c->active_head;
+        // find first node that's admissible
+        while(tail->x < width)
+            tail = tail->next;
+        while(tail) {
+            int xpos = tail->x - width;
+            int y, waste;
+            STBRP_ASSERT(xpos >= 0);
+            // find the left position that matches this
+            while(node->next->x <= xpos) {
+                prev = &node->next;
+                node = node->next;
+            }
+            STBRP_ASSERT(node->next->x > xpos && node->x <= xpos);
+            y = stbrp__skyline_find_min_y(c, node, xpos, width, &waste);
+            if(y + height <= c->height) {
+                if(y <= best_y) {
+                    if(y < best_y || waste < best_waste || (waste == best_waste && xpos < best_x)) {
+                        best_x = xpos;
+                        STBRP_ASSERT(y <= best_y);
+                        best_y = y;
+                        best_waste = waste;
+                        best = prev;
+                    }
+                }
+            }
+            tail = tail->next;
+        }
+    }
+
+    fr.prev_link = best;
+    fr.x = best_x;
+    fr.y = best_y;
+    return fr;
+}
+
+static stbrp__findresult stbrp__skyline_pack_rectangle(stbrp_context * context, int width, int height)
+{
+    // find best position according to heuristic
+    stbrp__findresult res = stbrp__skyline_find_best_pos(context, width, height);
+    stbrp_node * node, * cur;
+
+    // bail if:
+    //    1. it failed
+    //    2. the best node doesn't fit (we don't always check this)
+    //    3. we're out of memory
+    if(res.prev_link == NULL || res.y + height > context->height || context->free_head == NULL) {
+        res.prev_link = NULL;
+        return res;
+    }
+
+    // on success, create new node
+    node = context->free_head;
+    node->x = (stbrp_coord) res.x;
+    node->y = (stbrp_coord)(res.y + height);
+
+    context->free_head = node->next;
+
+    // insert the new node into the right starting point, and
+    // let 'cur' point to the remaining nodes needing to be
+    // stiched back in
+
+    cur = *res.prev_link;
+    if(cur->x < res.x) {
+        // preserve the existing one, so start testing with the next one
+        stbrp_node * next = cur->next;
+        cur->next = node;
+        cur = next;
+    }
+    else {
+        *res.prev_link = node;
+    }
+
+    // from here, traverse cur and free the nodes, until we get to one
+    // that shouldn't be freed
+    while(cur->next && cur->next->x <= res.x + width) {
+        stbrp_node * next = cur->next;
+        // move the current node to the free list
+        cur->next = context->free_head;
+        context->free_head = cur;
+        cur = next;
+    }
+
+    // stitch the list back in
+    node->next = cur;
+
+    if(cur->x < res.x + width)
+        cur->x = (stbrp_coord)(res.x + width);
+
+#ifdef _DEBUG
+    cur = context->active_head;
+    while(cur->x < context->width) {
+        STBRP_ASSERT(cur->x < cur->next->x);
+        cur = cur->next;
+    }
+    STBRP_ASSERT(cur->next == NULL);
+
+    {
+        int count = 0;
+        cur = context->active_head;
+        while(cur) {
+            cur = cur->next;
+            ++count;
+        }
+        cur = context->free_head;
+        while(cur) {
+            cur = cur->next;
+            ++count;
+        }
+        STBRP_ASSERT(count == context->num_nodes + 2);
+    }
+#endif
+
+    return res;
+}
+
+static int STBRP__CDECL rect_height_compare(const void * a, const void * b)
+{
+    const stbrp_rect * p = (const stbrp_rect *) a;
+    const stbrp_rect * q = (const stbrp_rect *) b;
+    if(p->h > q->h)
+        return -1;
+    if(p->h < q->h)
+        return  1;
+    return (p->w > q->w) ? -1 : (p->w < q->w);
+}
+
+static int STBRP__CDECL rect_original_order(const void * a, const void * b)
+{
+    const stbrp_rect * p = (const stbrp_rect *) a;
+    const stbrp_rect * q = (const stbrp_rect *) b;
+    return (p->was_packed < q->was_packed) ? -1 : (p->was_packed > q->was_packed);
+}
+
+STBRP_DEF int stbrp_pack_rects(stbrp_context * context, stbrp_rect * rects, int num_rects)
+{
+    int i, all_rects_packed = 1;
+
+    // we use the 'was_packed' field internally to allow sorting/unsorting
+    for(i = 0; i < num_rects; ++i) {
+        rects[i].was_packed = i;
+    }
+
+    // sort according to heuristic
+    STBRP_SORT(rects, num_rects, sizeof(rects[0]), rect_height_compare);
+
+    for(i = 0; i < num_rects; ++i) {
+        if(rects[i].w == 0 || rects[i].h == 0) {
+            rects[i].x = rects[i].y = 0;  // empty rect needs no space
+        }
+        else {
+            stbrp__findresult fr = stbrp__skyline_pack_rectangle(context, rects[i].w, rects[i].h);
+            if(fr.prev_link) {
+                rects[i].x = (stbrp_coord) fr.x;
+                rects[i].y = (stbrp_coord) fr.y;
+            }
+            else {
+                rects[i].x = rects[i].y = STBRP__MAXVAL;
+            }
+        }
+    }
+
+    // unsort
+    STBRP_SORT(rects, num_rects, sizeof(rects[0]), rect_original_order);
+
+    // set was_packed flags and all_rects_packed status
+    for(i = 0; i < num_rects; ++i) {
+        rects[i].was_packed = !(rects[i].x == STBRP__MAXVAL && rects[i].y == STBRP__MAXVAL);
+        if(!rects[i].was_packed)
+            all_rects_packed = 0;
+    }
+
+    // return the all_rects_packed status
+    return all_rects_packed;
+}
+#endif
+
+#if defined(__GNUC__) || defined(__clang__)
+    #pragma GCC diagnostic pop
+#endif
+
+/*
+------------------------------------------------------------------------------
+This software is available under 2 licenses -- choose whichever you prefer.
+------------------------------------------------------------------------------
+ALTERNATIVE A - MIT License
+Copyright (c) 2017 Sean Barrett
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+------------------------------------------------------------------------------
+ALTERNATIVE B - Public Domain (www.unlicense.org)
+This is free and unencumbered software released into the public domain.
+Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
+software, either in source code form or as a compiled binary, for any purpose,
+commercial or non-commercial, and by any means.
+In jurisdictions that recognize copyright laws, the author or authors of this
+software dedicate any and all copyright interest in the software to the public
+domain. We make this dedication for the benefit of the public at large and to
+the detriment of our heirs and successors. We intend this dedication to be an
+overt act of relinquishment in perpetuity of all present and future rights to
+this software under copyright law.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+------------------------------------------------------------------------------
+*/

src/lv_conf_internal.h

@@ -2217,6 +2217,25 @@
     #endif
 #endif
 
+/*Tiny TTF library*/
+#ifndef LV_USE_TINY_TTF
+    #ifdef CONFIG_LV_USE_TINY_TTF
+        #define LV_USE_TINY_TTF CONFIG_LV_USE_TINY_TTF
+    #else
+        #define LV_USE_TINY_TTF 0
+    #endif
+#endif
+#if LV_USE_TINY_TTF
+    /*Load TTF data from files*/
+    #ifndef LV_TINY_TTF_FILE_SUPPORT
+        #ifdef CONFIG_LV_TINY_TTF_FILE_SUPPORT
+            #define LV_TINY_TTF_FILE_SUPPORT CONFIG_LV_TINY_TTF_FILE_SUPPORT
+        #else
+            #define LV_TINY_TTF_FILE_SUPPORT 0
+        #endif
+    #endif
+#endif
+
 /*Rlottie library*/
 #ifndef LV_USE_RLOTTIE
     #ifdef CONFIG_LV_USE_RLOTTIE

tests/CMakeLists.txt

@@ -334,6 +334,7 @@ add_library(test_common
         src/test_fonts/font_1.c
         src/test_fonts/font_2.c
         src/test_fonts/font_3.c
+        src/test_fonts/ubuntu_font.c
         unity/unity_support.c
         unity/unity.c
 )
@@ -363,7 +364,7 @@ foreach( test_case_fname ${TEST_CASE_FILES} )
         ${test_case_fname}
         ${test_runner_fname}
     )
-    target_link_libraries(${test_name} test_common lvgl_examples lvgl_demos lvgl png ${TEST_LIBS})
+    target_link_libraries(${test_name} test_common lvgl_examples lvgl_demos lvgl png m ${TEST_LIBS})
     target_include_directories(${test_name} PUBLIC ${TEST_INCLUDE_DIRS})
     target_compile_options(${test_name} PUBLIC ${LVGL_TESTFILE_COMPILE_OPTIONS})
 

tests/src/lv_test_conf.h

@@ -20,6 +20,8 @@ extern "C" {
  *      DEFINES
  *********************/
 
+#define LV_USE_TINY_TTF 1
+
 void lv_test_assert_fail(void);
 #define LV_ASSERT_HANDLER lv_test_assert_fail();
 

tests/src/test_cases/test_tiny_ttf.c

@@ -0,0 +1,49 @@
+#if LV_BUILD_TEST
+#include "../lvgl.h"
+
+#include "unity/unity.h"
+
+void setUp(void)
+{
+    /* Function run before every test */
+}
+
+void tearDown(void)
+{
+    /* Function run after every test */
+}
+
+void test_tiny_ttf_rendering_test(void)
+{
+#if LV_USE_TINY_TTF
+    /*Create a font*/
+    extern const uint8_t ubuntu_font[];
+    extern size_t ubuntu_font_size;
+    lv_font_t * font = lv_tiny_ttf_create_data(ubuntu_font, ubuntu_font_size, 30);
+
+    /*Create style with the new font*/
+    static lv_style_t style;
+    lv_style_init(&style);
+    lv_style_set_text_font(&style, font);
+    lv_style_set_text_align(&style, LV_TEXT_ALIGN_CENTER);
+    lv_style_set_bg_opa(&style, LV_OPA_COVER);
+    lv_style_set_bg_color(&style, lv_color_hex(0xffaaaa));
+
+    /*Create a label with the new style*/
+    lv_obj_t * label = lv_label_create(lv_scr_act());
+    lv_obj_add_style(label, &style, 0);
+    lv_label_set_text(label, "Hello world\n"
+                      "I'm a font created with Tiny TTF\n"
+                      "Accents: ÁÉÍÓÖŐÜŰ áéíóöőüű");
+    lv_obj_center(label);
+
+    TEST_ASSERT_EQUAL_SCREENSHOT("tiny_ttf_1.png");
+
+    lv_obj_del(label);
+    lv_tiny_ttf_destroy(font);
+#else
+    TEST_PASS();
+#endif
+}
+
+#endif