loader png: support static png loader

Copied only necessary decoding functions from the lodepng opensource.
See: https://lodev.org/lodepng/

additional changes:
- disabled crc for the optimal size.
- converted the format bgr -> rgb for our png example.

Still we don't have a concrete idea for the image formats,
We should fix the converting methods between bgra <-> rgba.

@Issue: https://github.com/Samsung/thorvg/issues/594

src/loaders/external_jpg/tvgJpgLoader.cpp

@@ -74,6 +74,8 @@ bool JpgLoader::open(const string& path)
     data = (unsigned char *) malloc(size);
     if (!data) goto finalize;
 
+    freeData = true;
+
     if (fread(data, size, 1, jpegFile) < 1) goto failure;
 
     int width, height, subSample, colorSpace;
@@ -85,7 +87,6 @@ bool JpgLoader::open(const string& path)
     w = static_cast<float>(width);
     h = static_cast<float>(height);
     ret = true;
-    freeData = true;
 
     goto finalize;
 
@@ -112,6 +113,7 @@ bool JpgLoader::open(const char* data, uint32_t size, bool copy)
         freeData = true;
     } else {
         this->data = (unsigned char *) data;
+        freeData = false;
     }
 
     w = static_cast<float>(width);

src/loaders/png/meson.build

@@ -1,5 +1,7 @@
 source_file = [
+   'tvgLodePng.h',
    'tvgPngLoader.h',
+   'tvgLodePng.cpp',
    'tvgPngLoader.cpp',
 ]
 

src/loaders/png/tvgLodePng.h

@@ -0,0 +1,174 @@
+/*
+ * Copyright (c) 2020-2021 Samsung Electronics Co., Ltd. All rights reserved.
+
+ * 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.
+ */
+
+/*
+  LodePNG version 20200306
+
+  Copyright (c) 2005-2020 Lode Vandevenne
+
+  This software is provided 'as-is', without any express or implied
+  warranty. In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+      1. The origin of this software must not be misrepresented; you must not
+      claim that you wrote the original software. If you use this software
+      in a product, an acknowledgment in the product documentation would be
+      appreciated but is not required.
+
+      2. Altered source versions must be plainly marked as such, and must not be
+      misrepresented as being the original software.
+
+      3. This notice may not be removed or altered from any source
+      distribution.
+*/
+
+#ifndef _TVG_LODEPNG_H_
+#define _TVG_LODEPNG_H_
+
+#include <stddef.h>
+
+/*The PNG color types (also used for raw image).*/
+enum LodePNGColorType
+{
+    LCT_GREY = 0, /*grayscale: 1,2,4,8,16 bit*/
+    LCT_RGB = 2, /*RGB: 8,16 bit*/
+    LCT_PALETTE = 3, /*palette: 1,2,4,8 bit*/
+    LCT_GREY_ALPHA = 4, /*grayscale with alpha: 8,16 bit*/
+    LCT_RGBA = 6, /*RGB with alpha: 8,16 bit*/
+    /*LCT_MAX_OCTET_VALUE lets the compiler allow this enum to represent any invalid
+    byte value from 0 to 255 that could be present in an invalid PNG file header. Do
+    not use, compare with or set the name LCT_MAX_OCTET_VALUE, instead either use
+    the valid color type names above, or numeric values like 1 or 7 when checking for
+    particular disallowed color type byte values, or cast to integer to print it.*/
+    LCT_MAX_OCTET_VALUE = 255
+};
+
+/*Settings for zlib decompression*/
+struct LodePNGDecompressSettings
+{
+    /* Check LodePNGDecoderSettings for more ignorable errors such as ignore_crc */
+    unsigned ignore_adler32; /*if 1, continue and don't give an error message if the Adler32 checksum is corrupted*/
+    unsigned ignore_nlen; /*ignore complement of len checksum in uncompressed blocks*/
+
+    /*use custom zlib decoder instead of built in one (default: null)*/
+    unsigned (*custom_zlib)(unsigned char**, size_t*, const unsigned char*, size_t, const LodePNGDecompressSettings*);
+    /*use custom deflate decoder instead of built in one (default: null) if custom_zlib is not null, custom_inflate is ignored (the zlib format uses deflate)*/
+    unsigned (*custom_inflate)(unsigned char**, size_t*, const unsigned char*, size_t, const LodePNGDecompressSettings*);
+
+    const void* custom_context; /*optional custom settings for custom functions*/
+};
+
+/*
+  Color mode of an image. Contains all information required to decode the pixel
+  bits to RGBA colors. This information is the same as used in the PNG file
+  format, and is used both for PNG and raw image data in LodePNG.
+*/
+struct LodePNGColorMode
+{
+    /*header (IHDR)*/
+    LodePNGColorType colortype; /*color type, see PNG standard or documentation further in this header file*/
+    unsigned bitdepth;  /*bits per sample, see PNG standard or documentation further in this header file*/
+
+    /*
+      palette (PLTE and tRNS)
+
+      Dynamically allocated with the colors of the palette, including alpha.
+      This field may not be allocated directly, use lodepng_color_mode_init first,
+      then lodepng_palette_add per color to correctly initialize it (to ensure size
+      of exactly 1024 bytes).
+
+      The alpha channels must be set as well, set them to 255 for opaque images.
+
+      When decoding, by default you can ignore this palette, since LodePNG already
+      fills the palette colors in the pixels of the raw RGBA output.
+
+      The palette is only supported for color type 3.
+    */
+    unsigned char* palette; /*palette in RGBARGBA... order. Must be either 0, or when allocated must have 1024 bytes*/
+    size_t palettesize; /*palette size in number of colors (amount of used bytes is 4 * palettesize)*/
+
+    /*
+      transparent color key (tRNS)
+
+      This color uses the same bit depth as the bitdepth value in this struct, which can be 1-bit to 16-bit.
+      For grayscale PNGs, r, g and b will all 3 be set to the same.
+
+      When decoding, by default you can ignore this information, since LodePNG sets
+      pixels with this key to transparent already in the raw RGBA output.
+
+      The color key is only supported for color types 0 and 2.
+    */
+    unsigned key_defined; /*is a transparent color key given? 0 = false, 1 = true*/
+    unsigned key_r;       /*red/grayscale component of color key*/
+    unsigned key_g;       /*green component of color key*/
+    unsigned key_b;       /*blue component of color key*/
+};
+
+/*Information about the PNG image, except pixels, width and height.*/
+struct LodePNGInfo
+{
+    /*header (IHDR), palette (PLTE) and transparency (tRNS) chunks*/
+    unsigned compression_method;/*compression method of the original file. Always 0.*/
+    unsigned filter_method;     /*filter method of the original file*/
+    unsigned interlace_method;  /*interlace method of the original file: 0=none, 1=Adam7*/
+    LodePNGColorMode color;     /*color type and bits, palette and transparency of the PNG file*/
+};
+
+/*
+  Settings for the decoder. This contains settings for the PNG and the Zlib
+  decoder, but not the Info settings from the Info structs.
+*/
+struct LodePNGDecoderSettings
+{
+    LodePNGDecompressSettings zlibsettings; /*in here is the setting to ignore Adler32 checksums*/
+
+    /* Check LodePNGDecompressSettings for more ignorable errors such as ignore_adler32 */
+    unsigned ignore_crc; /*ignore CRC checksums*/
+    unsigned ignore_critical; /*ignore unknown critical chunks*/
+    unsigned ignore_end; /*ignore issues at end of file if possible (missing IEND chunk, too large chunk, ...)*/
+    /* TODO: make a system involving warnings with levels and a strict mode instead. Other potentially recoverable
+       errors: srgb rendering intent value, size of content of ancillary chunks, more than 79 characters for some
+       strings, placement/combination rules for ancillary chunks, crc of unknown chunks, allowed characters
+       in string keys, etc... */
+
+    unsigned color_convert; /*whether to convert the PNG to the color type you want. Default: yes*/
+};
+
+/*The settings, state and information for extended encoding and decoding.*/
+struct LodePNGState
+{
+    LodePNGDecoderSettings decoder; /*the decoding settings*/
+    LodePNGColorMode info_raw; /*specifies the format in which you would like to get the raw pixel buffer*/
+    LodePNGInfo info_png; /*info of the PNG image obtained after decoding*/
+    unsigned error;
+};
+
+void lodepng_state_init(LodePNGState* state);
+void lodepng_state_cleanup(LodePNGState* state);
+unsigned lodepng_decode(unsigned char** out, unsigned* w, unsigned* h, LodePNGState* state, const unsigned char* in, size_t insize);
+unsigned lodepng_inspect(unsigned* w, unsigned* h, LodePNGState* state, const unsigned char* in, size_t insize);
+
+#endif //_TVG_LODEPNG_H_

src/loaders/png/tvgPngLoader.cpp

@@ -19,14 +19,24 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-
+#include <memory.h>
 #include "tvgLoader.h"
 #include "tvgPngLoader.h"
 
+
 /************************************************************************/
 /* Internal Class Implementation                                        */
 /************************************************************************/
 
+void PngLoader::clear()
+{
+    lodepng_state_cleanup(&state);
+
+    if (freeData) free(data);
+    data = nullptr;
+    size = 0;
+    freeData = false;
+}
 
 
 /************************************************************************/
@@ -35,51 +45,115 @@
 
 PngLoader::PngLoader()
 {
-    //TODO:
+    lodepng_state_init(&state);
 }
 
 
 PngLoader::~PngLoader()
 {
-    //TODO:
+    if (freeData) free(data);
 }
 
 
 bool PngLoader::open(const string& path)
 {
-    //TODO:
+    clear();
 
-    return false;
+    auto pngFile = fopen(path.c_str(), "rb");
+    if (!pngFile) return false;
+
+    auto ret = false;
+
+    //determine size
+    if (fseek(pngFile, 0, SEEK_END) < 0) goto finalize;
+    if (((size = ftell(pngFile)) < 1)) goto finalize;
+    if (fseek(pngFile, 0, SEEK_SET)) goto finalize;
+
+    data = (unsigned char *) malloc(size);
+    if (!data) goto finalize;
+
+    freeData = true;
+
+    if (fread(data, size, 1, pngFile) < 1) goto failure;
+
+    lodepng_state_init(&state);
+
+    unsigned int width, height;
+    if (lodepng_inspect(&width, &height, &state, data, size) > 0) goto failure;
+
+    w = static_cast<float>(width);
+    h = static_cast<float>(height);
+    ret = true;
+
+    goto finalize;
+
+failure:
+    clear();
+
+finalize:
+    fclose(pngFile);
+    return ret;
 }
 
 
 bool PngLoader::open(const char* data, uint32_t size, bool copy)
 {
-    //TODO:
+    clear();
 
-    return false;
+    lodepng_state_init(&state);
+    
+    unsigned int width, height;
+    if (lodepng_inspect(&width, &height, &state, (unsigned char*)(data), size) > 0) return false;
+
+    if (copy) {
+        this->data = (unsigned char *) malloc(size);
+        if (!this->data) return false;
+        memcpy((unsigned char *)this->data, data, size);
+        freeData = true;
+    } else {
+        this->data = (unsigned char *) data;
+        freeData = false;
+    }
+
+    w = static_cast<float>(width);
+    h = static_cast<float>(height);
+    this->size = size;
+
+    return true;
 }
 
 
 bool PngLoader::read()
 {
-    //TODO:
+    if (!data || w <= 0 || h <= 0) return false;
 
-    return false;
+    TaskScheduler::request(this);
+
+    return true;
 }
 
 
 bool PngLoader::close()
 {
-    //TODO:
+    this->done();
 
-    return false;
+    clear();
+    return true;
 }
 
 
 const uint32_t* PngLoader::pixels()
 {
-    //TODO:
+    this->done();
 
-    return nullptr;
+    return (const uint32_t*) image;
+}
+
+
+void PngLoader::run(unsigned tid)
+{
+    auto width = static_cast<unsigned>(w);
+    auto height = static_cast<unsigned>(h);
+
+    lodepng_decode(&image, &width, &height, &state, data, size);
 }

src/loaders/png/tvgPngLoader.h

@@ -22,9 +22,21 @@
 #ifndef _TVG_PNG_LOADER_H_
 #define _TVG_PNG_LOADER_H_
 
-//TODO: Use Task?
-class PngLoader : public LoadModule
+#include "tvgLodePng.h"
+#include "tvgTaskScheduler.h"
+
+
+class PngLoader : public LoadModule, public Task
 {
+private:
+    LodePNGState state;
+    unsigned char* data = nullptr;
+    unsigned char *image = nullptr;
+    unsigned long size = 0;
+    bool freeData = false;
+
+    void clear();
+
 public:
     PngLoader();
     ~PngLoader();
@@ -36,6 +48,8 @@ public:
     bool close() override;
 
     const uint32_t* pixels() override;
+
+    void run(unsigned tid) override;
 };
 
 #endif //_TVG_PNG_LOADER_H_