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"
23 #include <dali/integration-api/bitmap.h>
24 #include <dali/integration-api/debug.h>
25 #include <dali/public-api/images/image.h>
26 #include <dali/public-api/images/image-attributes.h>
27 #include "dali/public-api/math/math-utils.h"
28 #include "dali/public-api/math/vector2.h"
29 #include "platform-capabilities.h"
34 using Integration::Bitmap;
35 using Dali::Integration::PixelBuffer;
43 // simple class to enforce clean-up of PNG structures
46 auto_png(png_structp& _png, png_infop& _info)
56 png_destroy_read_struct(&png, &info, NULL);
62 }; // struct auto_png;
64 bool LoadPngHeader(FILE *fp, unsigned int &width, unsigned int &height, png_structp &png, png_infop &info)
66 png_byte header[8] = { 0 };
68 // Check header to see if it is a PNG file
69 size_t size = fread(header, 1, 8, fp);
75 if(png_sig_cmp(header, 0, 8))
80 png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
84 DALI_LOG_WARNING("Can't create PNG read structure\n");
88 info = png_create_info_struct(png);
91 DALI_LOG_WARNING("png_create_info_struct failed\n");
97 if(setjmp(png_jmpbuf(png)))
99 DALI_LOG_WARNING("error during png_init_io\n");
103 png_init_io(png, fp);
104 png_set_sig_bytes(png, 8);
107 png_read_info(png, info);
110 width = png_get_image_width(png, info);
111 height = png_get_image_height(png, info);
116 } // namespace - anonymous
118 bool LoadPngHeader(FILE *fp, const ImageAttributes& attributes, unsigned int &width, unsigned int &height )
120 png_structp png = NULL;
121 png_infop info = NULL;
122 auto_png autoPng(png, info);
124 bool success = LoadPngHeader(fp, width, height, png, info);
129 bool LoadBitmapFromPng( FILE *fp, Bitmap& bitmap, ImageAttributes& attributes, const ResourceLoadingClient& client )
131 png_structp png = NULL;
132 png_infop info = NULL;
133 auto_png autoPng(png, info);
135 /// @todo: consider parameters
137 unsigned int width, height;
138 unsigned char *pixels;
140 unsigned int bpp = 0; // bytes per pixel
143 // Load info from the header
144 if( !LoadPngHeader(fp, width, height, png, info) )
149 Pixel::Format pixelFormat = Pixel::RGBA8888;
151 // decide pixel format
152 unsigned int colordepth = png_get_bit_depth(png, info);
154 // Ask PNGLib to convert high precision images into something we can use:
155 if (colordepth == 16)
157 png_set_strip_16(png);
161 png_byte colortype = png_get_color_type(png, info);
163 if(colortype == PNG_COLOR_TYPE_GRAY)
169 pixelFormat = Pixel::L8;
179 else if(colortype == PNG_COLOR_TYPE_GRAY_ALPHA)
185 pixelFormat = Pixel::LA88;
195 else if(colortype == PNG_COLOR_TYPE_RGB )
201 pixelFormat = Pixel::RGB888;
205 case 5: /// @todo is this correct for RGB16 5-6-5 ?
207 pixelFormat = Pixel::RGB565;
217 else if(colortype == PNG_COLOR_TYPE_RGBA)
223 pixelFormat = Pixel::RGBA8888;
233 else if(colortype == PNG_COLOR_TYPE_PALETTE)
241 /* Expand paletted or RGB images with transparency to full alpha channels
242 * so the data will be available as RGBA quartets. PNG_INFO_tRNS = 0x10
244 if(png_get_valid(png, info, PNG_INFO_tRNS) == 0x10)
246 pixelFormat = Pixel::RGBA8888;
251 pixelFormat = Pixel::RGB888;
252 png_set_packing(png);
253 png_set_packswap(png);
254 png_set_palette_to_rgb(png);
268 DALI_LOG_WARNING( "Unsupported png format\n" );
273 bpp = Pixel::GetBytesPerPixel(pixelFormat);
275 png_read_update_info(png, info);
277 if(setjmp(png_jmpbuf(png)))
279 DALI_LOG_WARNING("error during png_read_image\n");
283 unsigned int rowBytes = png_get_rowbytes(png, info);
285 unsigned int bufferWidth = GetTextureDimension(width);
286 unsigned int bufferHeight = GetTextureDimension(height);
287 unsigned int stride = bufferWidth*bpp;
289 // not sure if this ever happens
290 if( rowBytes > stride )
292 stride = GetTextureDimension(rowBytes);
293 bufferWidth = stride / bpp;
296 // decode the whole image into bitmap buffer
297 pixels = bitmap.GetPackedPixelsProfile()->ReserveBuffer(pixelFormat, width, height, bufferWidth, bufferHeight);
299 DALI_ASSERT_DEBUG(pixels);
300 rows = (png_bytep*) malloc(sizeof(png_bytep) * height);
301 for(y=0; y<height; y++)
303 rows[y] = (png_byte*) (pixels + y * stride);
307 png_read_image(png, rows);
309 // set the attributes
310 attributes.SetSize( width, height );
311 attributes.SetPixelFormat( pixelFormat );
318 // simple class to enforce clean-up of PNG structures
321 AutoPngWrite(png_structp& _png, png_infop& _info)
325 DALI_ASSERT_DEBUG(&_png != 0 && &_info != 0);
332 png_destroy_write_struct(&png, &info);
338 }; // struct AutoPngWrite;
342 // Custom libpng write callbacks that buffer to a vector instead of a file:
345 * extern "C" linkage is used because this is a callback that we pass to a C
346 * library which is part of the underlying platform and so potentially compiled
347 * as C rather than C++.
348 * @see http://stackoverflow.com/a/2594222
350 extern "C" void WriteData(png_structp png_ptr, png_bytep data, png_size_t length)
352 using Dali::SlpPlatform::PngBuffer;
353 DALI_ASSERT_DEBUG(png_ptr && data);
354 if(!png_ptr || !data)
358 // Make sure we don't try to propagate a C++ exception up the call stack of a pure C library:
360 // Recover our buffer for writing into:
361 PngBuffer* const encoded_img = (PngBuffer*) png_get_io_ptr(png_ptr);
364 const PngBuffer::size_type bufferSize = encoded_img->size();
365 encoded_img->resize(encoded_img->size() + length); //< Can throw OOM.
366 PngBuffer::value_type* const bufferBack = &((*encoded_img)[bufferSize]);
367 memcpy(bufferBack, data, length);
371 DALI_LOG_ERROR("PNG buffer for write to memory was passed from libpng as null.");
375 DALI_LOG_ERROR("C++ Exception caught");
379 /** Override the flush with a NOP to prevent libpng trying cstdlib file io. */
380 extern "C" void FlushData(png_structp png_ptr)
383 Debug::LogMessage(Debug::DebugInfo, "PNG Flush");
384 #endif // DEBUG_ENABLED
389 * Potential improvements:
390 * 1. Detect <= 256 colours and write in palette mode.
391 * 2. Detect grayscale (will early-out quickly for colour images).
392 * 3. Store colour space / gamma correction info related to the device screen?
393 * http://www.libpng.org/pub/png/book/chapter10.html
394 * 4. Refactor with callers to write straight through to disk and save keeping a big buffer around.
395 * 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)>.
396 * 6. Set the modification time with png_set_tIME(png_ptr, info_ptr, mod_time);
397 * 7. If caller asks for no compression, bypass libpng and blat raw data to
398 * disk, topped and tailed with header/tail blocks.
400 bool EncodeToPng( const unsigned char* const pixelBuffer, PngBuffer& encodedPixels, std::size_t width, std::size_t height, Pixel::Format pixelFormat )
402 // Translate pixel format enum:
403 int pngPixelFormat = -1;
404 unsigned pixelBytes = 0;
405 bool rgbaOrder = true;
407 // Account for RGB versus BGR and presence of alpha in input pixels:
408 switch( pixelFormat )
412 pngPixelFormat = PNG_COLOR_TYPE_RGB;
416 case Pixel::BGRA8888:
419 ///! No break: fall through:
421 case Pixel::RGBA8888:
423 pngPixelFormat = PNG_COLOR_TYPE_RGB_ALPHA;
429 DALI_LOG_ERROR( "Unsupported pixel format for encoding to PNG." );
434 const int interlace = PNG_INTERLACE_NONE;
436 png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
441 /* Allocate/initialize the image information data. REQUIRED */
442 png_infop info_ptr = png_create_info_struct( png_ptr );
445 png_destroy_write_struct(&png_ptr, NULL);
449 /* Set error handling. REQUIRED if you aren't supplying your own
450 * error handling functions in the png_create_write_struct() call.
452 if(setjmp(png_jmpbuf(png_ptr)))
454 png_destroy_write_struct(&png_ptr, &info_ptr);
458 // Since we are going to write to memory instead of a file, lets provide
459 // libpng with a custom write function and ask it to pass back our
460 // std::vector buffer each time it calls back to flush data to "file":
461 png_set_write_fn(png_ptr, &encodedPixels, WriteData, FlushData);
463 // png_set_compression_level( png_ptr, Z_BEST_COMPRESSION);
464 png_set_compression_level(png_ptr, Z_BEST_SPEED);
465 // png_set_compression_level( png_ptr, Z_NO_COMPRESSION); //! We could just generate png directly without libpng in this case.
467 // Explicitly limit the number of filters used per scanline to speed us up:
468 // png_set_filter(png_ptr, 0, PNG_FILTER_NONE); ///!ToDo: Try this once baseline profile is in place.
472 // PNG_FILTER_PAETH |
474 // Play with Zlib parameters in optimisation phase:
475 // png_set_compression_mem_level(png_ptr, 8);
476 // png_set_compression_strategy(png_ptr,
477 // Z_DEFAULT_STRATEGY);
478 // png_set_compression_window_bits(png_ptr, 15);
479 // png_set_compression_method(png_ptr, 8);
480 // png_set_compression_buffer_size(png_ptr, 8192)
482 // Let lib_png know if the pixel bytes are in BGR(A) order:
485 png_set_bgr( png_ptr );
488 // Set the image information:
489 png_set_IHDR(png_ptr, info_ptr, width, height, 8,
490 pngPixelFormat, interlace,
491 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
493 // Start to output the PNG data to our buffer:
494 png_write_info(png_ptr, info_ptr);
497 const unsigned row_step = width * pixelBytes;
498 png_bytep row_ptr = const_cast<png_bytep>(pixelBuffer);
499 const png_bytep row_end = row_ptr + height * row_step;
500 for(; row_ptr < row_end; row_ptr += row_step)
502 png_write_row(png_ptr, row_ptr);
505 /* It is REQUIRED to call this to finish writing the rest of the file */
506 png_write_end(png_ptr, info_ptr);
507 /* Clean up after the write, and free any memory allocated */
508 png_destroy_write_struct(&png_ptr, &info_ptr);
512 } // namespace SlpPlatform