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Png.cpp

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00001 /*
00002     Copyright (c) 2005, Quentin Lequy and Romain Gaucher
00003     All rights reserved.
00004 
00005     Redistribution and use in source and binary forms, with or 
00006     without modification, are permitted provided that the following 
00007     conditions are met:
00008 
00009         * Redistributions of source code must retain the above copyright 
00010           notice, this list of conditions and the following disclaimer.
00011 
00012         * Redistributions in binary form must reproduce the above copyright 
00013           notice, this list of conditions and the following disclaimer in the 
00014           documentation and/or other materials provided with the distribution.
00015 
00016         * Neither the name of Quentin Lequy or Romain Gaucher nor the names 
00017           of its contributors may be used to endorse or promote products 
00018           derived from this software without specific prior written permission.
00019 
00020     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
00021     AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
00022     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
00023     ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
00024     LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
00025     DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
00026     SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 
00027     AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
00028     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
00029     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00030 */
00031 
00032 
00033 #include "Png.h"
00034 #include <png.h>
00035 #include <iostream>
00036 
00037 namespace Modelib {
00038 
00039 using namespace std;
00040 
00041 PNGImage::~PNGImage() 
00042 {
00043   cerr << "PNG - destructor" << endl;
00044   if (fp!=NULL)
00045      fclose(fp);
00046   if (image)
00047   {
00048     for (unsigned i=0;i<height;i++)
00049           delete [] image[i];
00050     delete image;
00051   }
00052   delete [] row_pointers;
00053 }
00054 
00055 
00056 bool PNGImage::openFileRead() {
00057   if (fp!=NULL) {
00058      cerr << "file already opened\n" << endl;
00059     return false;   // can't open an already opened file
00060   }
00061 
00062   fp = fopen(filename.c_str(), "rb");
00063   if (!fp) {
00064     cerr << "couldn't open file " << filename << "for reading" << endl;;
00065     return false;           // couldn't open file
00066   }
00067     
00068   cerr << "opened file " <<  filename << endl;
00069   return true;
00070 }
00071 
00072 bool PNGImage::openFileWrite() {
00073   if (fp!=NULL) {
00074     cerr << "file already opened" << endl;
00075     return false;   // can't open an already opened file
00076   }
00077 
00078   fp = fopen(filename.c_str(), "wb");
00079   if (!fp) {
00080     return false;           // couldn't open file
00081   }
00082   return true;
00083 }
00084 
00085 bool PNGImage::isPNG(int bytesToCheck = 8) {
00086   if (fp==NULL) {
00087     if (openFileRead() == false) return false;
00088   }
00089 
00090   if (bytesToCheck > 8) {
00091     bytesToCheck=8;
00092     cerr << "bytesToCheck set to 8.  It cannot be more than 8." << endl;
00093   }
00094   else if (bytesToCheck < 1) {
00095     bytesToCheck=1;
00096     cerr << "bytesToCheck set to 1.  It cannot be less than 1." << endl;
00097   }
00098 
00099   // todo: check that fp is at start of file.
00100     
00101   char header[8];   // 8 is than maximum size that can be checked.
00102     
00103   int retValue = fread(header, 1, bytesToCheck, fp);
00104   if (retValue != bytesToCheck) {
00105     cerr << "couldn't read " << bytesToCheck << "bytes from file" << endl;
00106   }
00107 
00108   // use library to check if it's a valid PNG file
00109   bool valid;
00110   valid = ( png_sig_cmp((png_byte*)header, 0, bytesToCheck) == 0);
00111     
00112   return valid;
00113 }
00114 
00115 
00116 bool PNGImage::initReadStructs() {
00117   //  printf("initReadStructs: starting..." << endl;
00118 
00119   // initialise png_ptr
00120   //  printf("initReadStructs: initialising png_ptr..." << endl;
00121   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,    // from png.h
00122                    NULL, // ptr to struct for user error funct.
00123                    NULL, // ptr to user error function
00124                    NULL);// ptr to usr warning function
00125 
00126   if (png_ptr == NULL) {
00127     cerr << "initReadStructs: png_ptr was not able to be initialised" << endl;
00128     return false;
00129   }
00130 
00131 
00132   // initialise info_ptr
00133   //  printf("initReadStructs: initialising info_ptr..." << endl;
00134   info_ptr = png_create_info_struct(png_ptr);
00135   if (info_ptr == NULL) {
00136     cerr << "initReadStructs: info_ptr was not able to be initialised" << endl;
00137     png_destroy_read_struct(&png_ptr,
00138                 (png_infopp)NULL,   // ?
00139                 (png_infopp)NULL);  // ?
00140     return false;
00141   }
00142 
00143   // note: there is no end_info variable because I don't know what
00144   // it's for yet.  But if we need one then it's memory allocation
00145   // should happen here (once a variable has been declared in the
00146   // class).
00147 
00148   //  printf("initReadStructs: finished" << endl;
00149   return true;
00150 }
00151 
00152 
00153 bool PNGImage::initWriteStructs() {
00154   png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
00155                     NULL, // ptr to user error struct
00156                     NULL, // ptr to user error function
00157                     NULL);// ptr to user warning function
00158 
00159   if (!png_ptr) {
00160     cerr << "initWriteStructs: failed to init png_ptr" << endl;
00161     return false;
00162   }
00163 
00164   info_ptr = png_create_info_struct(png_ptr);
00165   if (!info_ptr) {
00166     cerr << "initWriteStructs: failed to init info_ptr" << endl;
00167     png_destroy_write_struct(&png_ptr,
00168                  (png_infopp)NULL);
00169     return false;
00170   }
00171 
00172   // prepare for errors.  Can't call setjmp() before png_ptr has been
00173   // allocated because the data inside png_ptr is access by png_jmpbuf!
00174   if (setjmp(png_jmpbuf(png_ptr))) {  // png_jmpbuf is a macro in pngconf.h
00175     cerr << "initReadStructs: setjmp returned non-zero (i.e. an error occured.)" << endl;
00176     png_destroy_read_struct(&png_ptr, &info_ptr, NULL /*end_info*/);
00177     return false;
00178   }
00179   png_init_io(png_ptr, fp);
00180   cerr << "initWriteStructs: complete" << endl;
00181   return true;
00182 }
00183 
00184 
00185 bool PNGImage::writeHeader() {
00186   cerr << "writeHeader: starting..." << endl;
00187   // prepare for errors.
00188   if (setjmp(png_jmpbuf(png_ptr))) {  // png_jmpbuf is a macro in pngconf.h
00189     cerr << "writeHeader: setjmp returned non-zero (i.e. an error occured.)" << endl;
00190     png_destroy_read_struct(&png_ptr, &info_ptr, NULL );
00191     return false;
00192   }
00193 
00194   cerr << "writeHeader: setting header" << endl;
00195   png_set_IHDR(png_ptr, info_ptr, width, height,
00196            8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
00197            PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
00198 
00199   cerr << "writeHeader: writing header" << endl;
00200   png_write_info(png_ptr, info_ptr);
00201   cerr << "writeHeader: finished." << endl;
00202 
00203   return true;
00204 }
00205 
00206 
00207 png_byte** PNGImage::writeImage_Start() {
00208   cerr << "writeImage: starting..." << endl;
00209   cerr << "image is " << height << " by " << width << endl;
00210   // prepare for errors.
00211   if (setjmp(png_jmpbuf(png_ptr))) {  // png_jmpbuf is a macro in pngconf.h
00212     cerr << "writeImage: setjmp returned non-zero (i.e. an error occured.)" << endl;
00213     png_destroy_read_struct(&png_ptr, &info_ptr, NULL /*end_info*/);
00214     return false;
00215   }
00216 
00217   for (unsigned k = 0; k < height; k++) {
00218     row_pointers[k] = image[k];
00219   }
00220 
00221   return image;
00222 }
00223 
00224 
00225 bool PNGImage::writeImage_End() {
00226   png_write_image(png_ptr, row_pointers);
00227   cerr << "writeImage: finished." << endl;
00228   return true;
00229 }
00230 
00231 bool PNGImage::writeEnd() {
00232   cerr << "writeEnd: starting..." << endl;
00233 
00234   // prepare for errors.
00235   if (setjmp(png_jmpbuf(png_ptr))) {  // png_jmpbuf is a macro in pngconf.h
00236     cerr << "writeEnd: setjmp returned non-zero (i.e. an error occured.)" << endl;
00237     png_destroy_read_struct(&png_ptr, &info_ptr, NULL /*end_info*/);
00238     return false;
00239   }
00240 
00241   png_write_end(png_ptr, NULL);  // NULL because we don't need to
00242                  // write any comments, etc.
00243 
00244   cerr << "writeEnd: finished" << endl;
00245   return true;
00246 }
00247 
00248 }
00249 

Généré le Sun Oct 2 19:13:12 2005 pour Modelib par  doxygen 1.4.4