2 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 #include "loader-png.h"
24 #include <dali/integration-api/bitmap.h>
25 #include <dali/integration-api/debug.h>
26 #include <dali/public-api/images/image.h>
27 #include <dali/public-api/images/image-attributes.h>
28 #include "dali/public-api/math/math-utils.h"
29 #include "dali/public-api/math/vector2.h"
30 #include "platform-capabilities.h"
35 using Integration::Bitmap;
36 using Dali::Integration::PixelBuffer;
44 // simple class to enforce clean-up of PNG structures
47 auto_png(png_structp& _png, png_infop& _info)
57 png_destroy_read_struct(&png, &info, NULL);
63 }; // struct auto_png;
65 bool LoadPngHeader(FILE *fp, unsigned int &width, unsigned int &height, png_structp &png, png_infop &info)
67 png_byte header[8] = { 0 };
69 // Check header to see if it is a PNG file
70 size_t size = fread(header, 1, 8, fp);
76 if(png_sig_cmp(header, 0, 8))
81 png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
85 DALI_LOG_WARNING("Can't create PNG read structure\n");
89 info = png_create_info_struct(png);
92 DALI_LOG_WARNING("png_create_info_struct failed\n");
98 if(setjmp(png_jmpbuf(png)))
100 DALI_LOG_WARNING("error during png_init_io\n");
104 png_init_io(png, fp);
105 png_set_sig_bytes(png, 8);
108 png_read_info(png, info);
111 width = png_get_image_width(png, info);
112 height = png_get_image_height(png, info);
117 } // namespace - anonymous
119 bool LoadPngHeader(FILE *fp, const ImageAttributes& attributes, unsigned int &width, unsigned int &height )
121 png_structp png = NULL;
122 png_infop info = NULL;
123 auto_png autoPng(png, info);
125 bool success = LoadPngHeader(fp, width, height, png, info);
130 bool LoadBitmapFromPng( FILE *fp, Bitmap& bitmap, ImageAttributes& attributes, const ResourceLoadingClient& client )
132 png_structp png = NULL;
133 png_infop info = NULL;
134 auto_png autoPng(png, info);
136 /// @todo: consider parameters
138 unsigned int width, height;
139 unsigned char *pixels;
141 unsigned int bpp = 0; // bytes per pixel
144 // Load info from the header
145 if( !LoadPngHeader(fp, width, height, png, info) )
150 Pixel::Format pixelFormat = Pixel::RGBA8888;
152 // decide pixel format
153 unsigned int colordepth = png_get_bit_depth(png, info);
155 // Ask PNGLib to convert high precision images into something we can use:
156 if (colordepth == 16)
158 png_set_strip_16(png);
162 png_byte colortype = png_get_color_type(png, info);
164 if(colortype == PNG_COLOR_TYPE_GRAY)
170 pixelFormat = Pixel::L8;
180 else if(colortype == PNG_COLOR_TYPE_GRAY_ALPHA)
186 pixelFormat = Pixel::LA88;
196 else if(colortype == PNG_COLOR_TYPE_RGB )
202 pixelFormat = Pixel::RGB888;
206 case 5: /// @todo is this correct for RGB16 5-6-5 ?
208 pixelFormat = Pixel::RGB565;
218 else if(colortype == PNG_COLOR_TYPE_RGBA)
224 pixelFormat = Pixel::RGBA8888;
234 else if(colortype == PNG_COLOR_TYPE_PALETTE)
242 /* Expand paletted or RGB images with transparency to full alpha channels
243 * so the data will be available as RGBA quartets. PNG_INFO_tRNS = 0x10
245 if(png_get_valid(png, info, PNG_INFO_tRNS) == 0x10)
247 pixelFormat = Pixel::RGBA8888;
252 pixelFormat = Pixel::RGB888;
253 png_set_packing(png);
254 png_set_packswap(png);
255 png_set_palette_to_rgb(png);
269 DALI_LOG_WARNING( "Unsupported png format\n" );
274 bpp = Pixel::GetBytesPerPixel(pixelFormat);
276 png_read_update_info(png, info);
278 if(setjmp(png_jmpbuf(png)))
280 DALI_LOG_WARNING("error during png_read_image\n");
284 unsigned int rowBytes = png_get_rowbytes(png, info);
286 unsigned int bufferWidth = GetTextureDimension(width);
287 unsigned int bufferHeight = GetTextureDimension(height);
288 unsigned int stride = bufferWidth*bpp;
290 // not sure if this ever happens
291 if( rowBytes > stride )
293 stride = GetTextureDimension(rowBytes);
294 bufferWidth = stride / bpp;
297 // decode the whole image into bitmap buffer
298 pixels = bitmap.GetPackedPixelsProfile()->ReserveBuffer(pixelFormat, width, height, bufferWidth, bufferHeight);
300 DALI_ASSERT_DEBUG(pixels);
301 rows = (png_bytep*) malloc(sizeof(png_bytep) * height);
302 for(y=0; y<height; y++)
304 rows[y] = (png_byte*) (pixels + y * stride);
308 png_read_image(png, rows);
310 // set the attributes
311 attributes.SetSize( width, height );
312 attributes.SetPixelFormat( pixelFormat );
319 // simple class to enforce clean-up of PNG structures
322 AutoPngWrite(png_structp& _png, png_infop& _info)
326 DALI_ASSERT_DEBUG(&_png != 0 && &_info != 0);
333 png_destroy_write_struct(&png, &info);
339 }; // struct AutoPngWrite;
343 // Custom libpng write callbacks that buffer to a vector instead of a file:
346 * extern "C" linkage is used because this is a callback that we pass to a C
347 * library which is part of the underlying platform and so potentially compiled
348 * as C rather than C++.
349 * @see http://stackoverflow.com/a/2594222
351 extern "C" void WriteData(png_structp png_ptr, png_bytep data, png_size_t length)
353 using Dali::SlpPlatform::PngBuffer;
354 DALI_ASSERT_DEBUG(png_ptr && data);
355 if(!png_ptr || !data)
359 // Make sure we don't try to propagate a C++ exception up the call stack of a pure C library:
361 // Recover our buffer for writing into:
362 PngBuffer* const encoded_img = (PngBuffer*) png_get_io_ptr(png_ptr);
365 const PngBuffer::size_type bufferSize = encoded_img->size();
366 encoded_img->resize(encoded_img->size() + length); //< Can throw OOM.
367 PngBuffer::value_type* const bufferBack = &((*encoded_img)[bufferSize]);
368 memcpy(bufferBack, data, length);
372 DALI_LOG_ERROR("PNG buffer for write to memory was passed from libpng as null.");
376 DALI_LOG_ERROR("C++ Exception caught");
380 /** Override the flush with a NOP to prevent libpng trying cstdlib file io. */
381 extern "C" void FlushData(png_structp png_ptr)
384 Debug::LogMessage(Debug::DebugInfo, "PNG Flush");
385 #endif // DEBUG_ENABLED
390 * Potential improvements:
391 * 1. Detect <= 256 colours and write in palette mode.
392 * 2. Detect grayscale (will early-out quickly for colour images).
393 * 3. Store colour space / gamma correction info related to the device screen?
394 * http://www.libpng.org/pub/png/book/chapter10.html
395 * 4. Refactor with callers to write straight through to disk and save keeping a big buffer around.
396 * 5. Prealloc buffer (reserve) to input size / <A number greater than 2 (expexcted few realloc but without using lots of memory) | 1 (expected zero reallocs but using a lot of memory)>.
397 * 6. Set the modification time with png_set_tIME(png_ptr, info_ptr, mod_time);
398 * 7. If caller asks for no compression, bypass libpng and blat raw data to
399 * disk, topped and tailed with header/tail blocks.
401 bool EncodeToPng( const unsigned char* const pixelBuffer, PngBuffer& encodedPixels, std::size_t width, std::size_t height, Pixel::Format pixelFormat )
403 // Translate pixel format enum:
404 int pngPixelFormat = -1;
405 unsigned pixelBytes = 0;
406 bool rgbaOrder = true;
408 // Account for RGB versus BGR and presence of alpha in input pixels:
409 switch( pixelFormat )
413 pngPixelFormat = PNG_COLOR_TYPE_RGB;
417 case Pixel::BGRA8888:
420 ///! No break: fall through:
422 case Pixel::RGBA8888:
424 pngPixelFormat = PNG_COLOR_TYPE_RGB_ALPHA;
430 DALI_LOG_ERROR( "Unsupported pixel format for encoding to PNG." );
435 const int interlace = PNG_INTERLACE_NONE;
437 png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
442 /* Allocate/initialize the image information data. REQUIRED */
443 png_infop info_ptr = png_create_info_struct( png_ptr );
446 png_destroy_write_struct(&png_ptr, NULL);
450 /* Set error handling. REQUIRED if you aren't supplying your own
451 * error handling functions in the png_create_write_struct() call.
453 if(setjmp(png_jmpbuf(png_ptr)))
455 png_destroy_write_struct(&png_ptr, &info_ptr);
459 // Since we are going to write to memory instead of a file, lets provide
460 // libpng with a custom write function and ask it to pass back our
461 // std::vector buffer each time it calls back to flush data to "file":
462 png_set_write_fn(png_ptr, &encodedPixels, WriteData, FlushData);
464 // png_set_compression_level( png_ptr, Z_BEST_COMPRESSION);
465 png_set_compression_level(png_ptr, Z_BEST_SPEED);
466 // png_set_compression_level( png_ptr, Z_NO_COMPRESSION); //! We could just generate png directly without libpng in this case.
468 // Explicitly limit the number of filters used per scanline to speed us up:
469 // png_set_filter(png_ptr, 0, PNG_FILTER_NONE); ///!ToDo: Try this once baseline profile is in place.
473 // PNG_FILTER_PAETH |
475 // Play with Zlib parameters in optimisation phase:
476 // png_set_compression_mem_level(png_ptr, 8);
477 // png_set_compression_strategy(png_ptr,
478 // Z_DEFAULT_STRATEGY);
479 // png_set_compression_window_bits(png_ptr, 15);
480 // png_set_compression_method(png_ptr, 8);
481 // png_set_compression_buffer_size(png_ptr, 8192)
483 // Let lib_png know if the pixel bytes are in BGR(A) order:
486 png_set_bgr( png_ptr );
489 // Set the image information:
490 png_set_IHDR(png_ptr, info_ptr, width, height, 8,
491 pngPixelFormat, interlace,
492 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
494 // Start to output the PNG data to our buffer:
495 png_write_info(png_ptr, info_ptr);
498 const unsigned row_step = width * pixelBytes;
499 png_bytep row_ptr = const_cast<png_bytep>(pixelBuffer);
500 const png_bytep row_end = row_ptr + height * row_step;
501 for(; row_ptr < row_end; row_ptr += row_step)
503 png_write_row(png_ptr, row_ptr);
506 /* It is REQUIRED to call this to finish writing the rest of the file */
507 png_write_end(png_ptr, info_ptr);
508 /* Clean up after the write, and free any memory allocated */
509 png_destroy_write_struct(&png_ptr, &info_ptr);
513 } // namespace SlpPlatform