Added ImFontAtlas::AddFontFromCompressedTTF() helper + binary_to_compressed_c.cpp tool

extra_fonts/binary_to_compressed_c.cpp

@@ -0,0 +1,330 @@
+// ImGui - binary_to_compressed_c.cpp
+// Helper tool to turn a file into a C array.
+// The data is first compressed with stb_compress() to reduce source code size a little.
+// Useful if you want to embed fonts into your code.
+// Note that the output array is likely to be bigger than the binary file..
+// Load compressed TTF fonts with ImGui::GetIO().Fonts->AddFontFromMemoryCompressedTTF()
+
+#define _CRT_SECURE_NO_WARNINGS
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <assert.h>
+
+const int COLUMNS = 12;
+
+// stb_compress* from stb.h - declaration
+typedef unsigned int stb_uint;
+typedef unsigned char stb_uchar;
+stb_uint stb_compress(stb_uchar *out,stb_uchar *in,stb_uint len);
+
+static bool binary_to_compressed_c(const char* filename, const char* symbol);
+
+int main(int argc, char** argv)
+{
+    if (argc < 3)
+    {
+        printf("Syntax: %s <inputfile> <symbolname>\n", argv[0]);
+        return 0;
+    }
+
+    binary_to_compressed_c(argv[1], argv[2]);
+    return 1;
+}
+
+bool binary_to_compressed_c(const char* filename, const char* symbol)
+{
+    // Read file
+    FILE* f = fopen(filename, "rb");
+    if (!f) return false;
+    int data_sz;
+    if (fseek(f, 0, SEEK_END) || (data_sz = (int)ftell(f)) == -1 || fseek(f, 0, SEEK_SET)) { fclose(f); return false; }
+    char* data = new char[data_sz+4];
+    if (fread(data, 1, data_sz, f) != (size_t)data_sz) { fclose(f); delete[] data; return false; }
+    memset((void *)(((char*)data) + data_sz), 0, 4);
+    fclose(f);
+
+    // Compress
+    int maxlen = data_sz + 512 + (data_sz >> 2) + sizeof(int); // total guess
+    char* compressed = new char[maxlen];
+    int compressed_sz = stb_compress((stb_uchar*)compressed, (stb_uchar*)data, data_sz);
+    memset(compressed + compressed_sz, 0, maxlen - compressed_sz);
+
+    // Output
+    FILE* out = stdout;
+    fprintf(out, "// File: '%s' (%d bytes)\n", filename, (int)data_sz);
+    fprintf(out, "// Exported using binary_to_compressed_c\n");
+    fprintf(out, "static const unsigned int %s_compressed_size = %d;\n", symbol, (int)compressed_sz);
+    fprintf(out, "static const unsigned int %s_compressed_data[%d/4] =\n{", symbol, (int)((compressed_sz+3)/4)*4);
+    int column = 0;
+    for (int i = 0; i < compressed_sz; i += 4)
+    {
+        unsigned int d = *(unsigned int*)(compressed + i);
+        if ((column++ % COLUMNS) == 0)
+            fprintf(out, "\n    0x%08x, ", d);
+        else
+            fprintf(out, "0x%08x, ", d);
+    }
+    fprintf(out, "\n};\n\n");
+
+    // Cleanup
+    delete[] data;
+    delete[] compressed;
+    return true;
+}
+
+// stb_compress* from stb.h - definition
+
+////////////////////           compressor         ///////////////////////
+
+static stb_uint stb_adler32(stb_uint adler32, stb_uchar *buffer, stb_uint buflen)
+{
+    const unsigned long ADLER_MOD = 65521;
+    unsigned long s1 = adler32 & 0xffff, s2 = adler32 >> 16;
+    unsigned long blocklen, i;
+
+    blocklen = buflen % 5552;
+    while (buflen) {
+        for (i=0; i + 7 < blocklen; i += 8) {
+            s1 += buffer[0], s2 += s1;
+            s1 += buffer[1], s2 += s1;
+            s1 += buffer[2], s2 += s1;
+            s1 += buffer[3], s2 += s1;
+            s1 += buffer[4], s2 += s1;
+            s1 += buffer[5], s2 += s1;
+            s1 += buffer[6], s2 += s1;
+            s1 += buffer[7], s2 += s1;
+
+            buffer += 8;
+        }
+
+        for (; i < blocklen; ++i)
+            s1 += *buffer++, s2 += s1;
+
+        s1 %= ADLER_MOD, s2 %= ADLER_MOD;
+        buflen -= blocklen;
+        blocklen = 5552;
+    }
+    return (s2 << 16) + s1;
+}
+
+static unsigned int stb_matchlen(stb_uchar *m1, stb_uchar *m2, stb_uint maxlen)
+{
+    stb_uint i;
+    for (i=0; i < maxlen; ++i)
+        if (m1[i] != m2[i]) return i;
+    return i;
+}
+
+// simple implementation that just takes the source data in a big block
+
+static stb_uchar *stb__out;
+static FILE      *stb__outfile;
+static stb_uint   stb__outbytes;
+
+static void stb__write(unsigned char v)
+{
+    fputc(v, stb__outfile);
+    ++stb__outbytes;
+}
+
+#define stb_out(v)    (stb__out ? *stb__out++ = (stb_uchar) (v) : stb__write((stb_uchar) (v)))
+
+static void stb_out2(stb_uint v)
+{
+    stb_out(v >> 8);
+    stb_out(v);
+}
+
+static void stb_out3(stb_uint v) { stb_out(v >> 16); stb_out(v >> 8); stb_out(v); }
+static void stb_out4(stb_uint v) { stb_out(v >> 24); stb_out(v >> 16);
+stb_out(v >> 8 ); stb_out(v);                  }
+
+static void outliterals(stb_uchar *in, int numlit)
+{
+    while (numlit > 65536) {
+        outliterals(in,65536);
+        in     += 65536;
+        numlit -= 65536;
+    }
+
+    if      (numlit ==     0)    ;
+    else if (numlit <=    32)    stb_out (0x000020 + numlit-1);
+    else if (numlit <=  2048)    stb_out2(0x000800 + numlit-1);
+    else /*  numlit <= 65536) */ stb_out3(0x070000 + numlit-1);
+
+    if (stb__out) {
+        memcpy(stb__out,in,numlit);
+        stb__out += numlit;
+    } else
+        fwrite(in, 1, numlit, stb__outfile);
+}
+
+static int stb__window = 0x40000; // 256K
+
+static int stb_not_crap(int best, int dist)
+{
+    return   ((best > 2  &&  dist <= 0x00100)     
+        || (best > 5  &&  dist <= 0x04000)
+        || (best > 7  &&  dist <= 0x80000));
+}
+
+static  stb_uint stb__hashsize = 32768;
+
+// note that you can play with the hashing functions all you
+// want without needing to change the decompressor
+#define stb__hc(q,h,c)      (((h) << 7) + ((h) >> 25) + q[c])
+#define stb__hc2(q,h,c,d)   (((h) << 14) + ((h) >> 18) + (q[c] << 7) + q[d])
+#define stb__hc3(q,c,d,e)   ((q[c] << 14) + (q[d] << 7) + q[e])
+
+static unsigned int stb__running_adler;
+
+static int stb_compress_chunk(stb_uchar *history,
+    stb_uchar *start,
+    stb_uchar *end,
+    int length,
+    int *pending_literals,
+    stb_uchar **chash,
+    stb_uint mask)
+{
+    (void)history;
+    int window = stb__window;
+    stb_uint match_max;
+    stb_uchar *lit_start = start - *pending_literals;
+    stb_uchar *q = start;
+
+#define STB__SCRAMBLE(h)   (((h) + ((h) >> 16)) & mask)
+
+    // stop short of the end so we don't scan off the end doing
+    // the hashing; this means we won't compress the last few bytes
+    // unless they were part of something longer
+    while (q < start+length && q+12 < end) {
+        int m;
+        stb_uint h1,h2,h3,h4, h;
+        stb_uchar *t;
+        int best = 2, dist=0;
+
+        if (q+65536 > end)
+            match_max = end-q;
+        else
+            match_max = 65536;
+
+#define stb__nc(b,d)  ((d) <= window && ((b) > 9 || stb_not_crap(b,d)))
+
+#define STB__TRY(t,p)  /* avoid retrying a match we already tried */ \
+    if (p ? dist != q-t : 1)                             \
+    if ((m = stb_matchlen(t, q, match_max)) > best)     \
+    if (stb__nc(m,q-(t)))                                \
+    best = m, dist = q - (t)
+
+        // rather than search for all matches, only try 4 candidate locations,
+        // chosen based on 4 different hash functions of different lengths.
+        // this strategy is inspired by LZO; hashing is unrolled here using the
+        // 'hc' macro
+        h = stb__hc3(q,0, 1, 2); h1 = STB__SCRAMBLE(h);
+        t = chash[h1]; if (t) STB__TRY(t,0);
+        h = stb__hc2(q,h, 3, 4); h2 = STB__SCRAMBLE(h);
+        h = stb__hc2(q,h, 5, 6);        t = chash[h2]; if (t) STB__TRY(t,1);
+        h = stb__hc2(q,h, 7, 8); h3 = STB__SCRAMBLE(h);
+        h = stb__hc2(q,h, 9,10);        t = chash[h3]; if (t) STB__TRY(t,1);
+        h = stb__hc2(q,h,11,12); h4 = STB__SCRAMBLE(h);
+        t = chash[h4]; if (t) STB__TRY(t,1);
+
+        // because we use a shared hash table, can only update it
+        // _after_ we've probed all of them
+        chash[h1] = chash[h2] = chash[h3] = chash[h4] = q;
+
+        if (best > 2)
+            assert(dist > 0);
+
+        // see if our best match qualifies
+        if (best < 3) { // fast path literals
+            ++q;
+        } else if (best > 2  &&  best <= 0x80    &&  dist <= 0x100) {
+            outliterals(lit_start, q-lit_start); lit_start = (q += best);
+            stb_out(0x80 + best-1);
+            stb_out(dist-1);
+        } else if (best > 5  &&  best <= 0x100   &&  dist <= 0x4000) {
+            outliterals(lit_start, q-lit_start); lit_start = (q += best);
+            stb_out2(0x4000 + dist-1);       
+            stb_out(best-1);
+        } else if (best > 7  &&  best <= 0x100   &&  dist <= 0x80000) {
+            outliterals(lit_start, q-lit_start); lit_start = (q += best);
+            stb_out3(0x180000 + dist-1);     
+            stb_out(best-1);
+        } else if (best > 8  &&  best <= 0x10000 &&  dist <= 0x80000) {
+            outliterals(lit_start, q-lit_start); lit_start = (q += best);
+            stb_out3(0x100000 + dist-1);     
+            stb_out2(best-1);
+        } else if (best > 9                      &&  dist <= 0x1000000) {
+            if (best > 65536) best = 65536;
+            outliterals(lit_start, q-lit_start); lit_start = (q += best);
+            if (best <= 0x100) {
+                stb_out(0x06);
+                stb_out3(dist-1);
+                stb_out(best-1);
+            } else {
+                stb_out(0x04);
+                stb_out3(dist-1);
+                stb_out2(best-1);
+            }
+        } else {  // fallback literals if no match was a balanced tradeoff
+            ++q;
+        }
+    }
+
+    // if we didn't get all the way, add the rest to literals
+    if (q-start < length)
+        q = start+length;
+
+    // the literals are everything from lit_start to q
+    *pending_literals = (q - lit_start);
+
+    stb__running_adler = stb_adler32(stb__running_adler, start, q - start);
+    return q - start;
+}
+
+static int stb_compress_inner(stb_uchar *input, stb_uint length)
+{
+    int literals = 0;
+    stb_uint len,i;
+
+    stb_uchar **chash;
+    chash = (stb_uchar**) malloc(stb__hashsize * sizeof(stb_uchar*));
+    if (chash == NULL) return 0; // failure
+    for (i=0; i < stb__hashsize; ++i)
+        chash[i] = NULL;
+
+    // stream signature
+    stb_out(0x57); stb_out(0xbc);
+    stb_out2(0);
+
+    stb_out4(0);       // 64-bit length requires 32-bit leading 0
+    stb_out4(length);
+    stb_out4(stb__window);
+
+    stb__running_adler = 1;
+
+    len = stb_compress_chunk(input, input, input+length, length, &literals, chash, stb__hashsize-1);
+    assert(len == length);
+
+    outliterals(input+length - literals, literals);
+
+    free(chash);
+
+    stb_out2(0x05fa); // end opcode
+
+    stb_out4(stb__running_adler);
+
+    return 1; // success
+}
+
+stb_uint stb_compress(stb_uchar *out, stb_uchar *input, stb_uint length)
+{
+    stb__out = out;
+    stb__outfile = NULL;
+
+    stb_compress_inner(input, length);
+
+    return stb__out - out;
+}

imgui.cpp

@@ -8101,18 +8101,10 @@ static unsigned int stb_decompress(unsigned char *output, unsigned char *i, unsi
 // Load embedded ProggyClean.ttf at size 13
 ImFont* ImFontAtlas::AddFontDefault()
 {
-    // Get compressed data
     unsigned int ttf_compressed_size;
     const void* ttf_compressed;
     GetDefaultCompressedFontDataTTF(&ttf_compressed, &ttf_compressed_size);
-
+    ImFont* font = AddFontFromMemoryCompressedTTF(ttf_compressed, ttf_compressed_size, 13.0f, GetGlyphRangesDefault(), 0);
-    // Decompress
-    const size_t buf_decompressed_size = stb_decompress_length((unsigned char*)ttf_compressed);
-    unsigned char* buf_decompressed = (unsigned char *)ImGui::MemAlloc(buf_decompressed_size);
-    stb_decompress(buf_decompressed, (unsigned char*)ttf_compressed, ttf_compressed_size);
-
-    // Add
-    ImFont* font = AddFontFromMemoryTTF(buf_decompressed, buf_decompressed_size, 13.0f, GetGlyphRangesDefault(), 0);
     font->DisplayOffset.y += 1;
     return font;
 }
@@ -8127,7 +8119,6 @@ ImFont* ImFontAtlas::AddFontFromFileTTF(const char* filename, float size_pixels,
         return NULL;
     }
 
-    // Add
     ImFont* font = AddFontFromMemoryTTF(data, data_size, size_pixels, glyph_ranges, font_no);
     return font;
 }
@@ -8157,6 +8148,18 @@ ImFont* ImFontAtlas::AddFontFromMemoryTTF(void* in_ttf_data, size_t in_ttf_data_
     return font;
 }
 
+ImFont* ImFontAtlas::AddFontFromMemoryCompressedTTF(const void* in_compressed_ttf_data, size_t in_compressed_ttf_data_size, float size_pixels, const ImWchar* glyph_ranges, int font_no)
+{
+    // Decompress
+    const size_t buf_decompressed_size = stb_decompress_length((unsigned char*)in_compressed_ttf_data);
+    unsigned char* buf_decompressed = (unsigned char *)ImGui::MemAlloc(buf_decompressed_size);
+    stb_decompress(buf_decompressed, (unsigned char*)in_compressed_ttf_data, in_compressed_ttf_data_size);
+
+    // Add
+    ImFont* font = AddFontFromMemoryTTF(buf_decompressed, buf_decompressed_size, size_pixels, glyph_ranges, font_no);
+    return font;
+}
+
 bool    ImFontAtlas::Build()
 {
     IM_ASSERT(InputData.size() > 0);

imgui.h

@@ -947,7 +947,8 @@ struct ImFontAtlas
     IMGUI_API ~ImFontAtlas();
     IMGUI_API ImFont*           AddFontDefault();
     IMGUI_API ImFont*           AddFontFromFileTTF(const char* filename, float size_pixels, const ImWchar* glyph_ranges = NULL, int font_no = 0);
-    IMGUI_API ImFont*           AddFontFromMemoryTTF(void* in_ttf_data, size_t in_ttf_data_size, float size_pixels, const ImWchar* glyph_ranges = NULL, int font_no = 0); // Pass ownership of 'in_ttf_data' memory.
+    IMGUI_API ImFont*           AddFontFromMemoryTTF(void* in_ttf_data, unsigned int in_ttf_data_size, float size_pixels, const ImWchar* glyph_ranges = NULL, int font_no = 0); // Pass ownership of 'in_ttf_data' memory, will be deleted after build
+    IMGUI_API ImFont*           AddFontFromMemoryCompressedTTF(const void* in_compressed_ttf_data, unsigned int in_compressed_ttf_data_size, float size_pixels, const ImWchar* glyph_ranges = NULL, int font_no = 0); // 'in_compressed_ttf_data' untouched and still owned by caller. compress with binary_to_compressed_c.
     IMGUI_API void              ClearTexData();             // Saves RAM once the texture has been copied to graphics memory.
     IMGUI_API void              Clear();