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e9c4b1a2 | 1 | ///////////////////////////////////////////////////////////////////////////// |
6d3d756a | 2 | // Name: src/common/imagjpeg.cpp |
e9c4b1a2 | 3 | // Purpose: wxImage JPEG handler |
b59ff3c9 | 4 | // Author: Vaclav Slavik |
e9c4b1a2 | 5 | // RCS-ID: $Id$ |
b59ff3c9 | 6 | // Copyright: (c) Vaclav Slavik |
65571936 | 7 | // Licence: wxWindows licence |
e9c4b1a2 JS |
8 | ///////////////////////////////////////////////////////////////////////////// |
9 | ||
e9c4b1a2 JS |
10 | // For compilers that support precompilation, includes "wx.h". |
11 | #include "wx/wxprec.h" | |
12 | ||
13 | #ifdef __BORLANDC__ | |
88a7a4e1 | 14 | #pragma hdrstop |
e9c4b1a2 JS |
15 | #endif |
16 | ||
c96ea657 | 17 | #if wxUSE_IMAGE && wxUSE_LIBJPEG |
ce4169a4 | 18 | |
88a7a4e1 WS |
19 | #include "wx/imagjpeg.h" |
20 | ||
8898456d WS |
21 | #ifndef WX_PRECOMP |
22 | #include "wx/log.h" | |
23 | #include "wx/app.h" | |
88a7a4e1 | 24 | #include "wx/intl.h" |
8898456d WS |
25 | #endif |
26 | ||
e9c4b1a2 JS |
27 | #include "wx/bitmap.h" |
28 | #include "wx/debug.h" | |
cb69afe0 | 29 | |
7beb59f3 | 30 | // NB: Some compilers define boolean type in Windows headers |
4c87eb44 | 31 | // (e.g. Watcom C++, but not Open Watcom). |
cb69afe0 VS |
32 | // This causes a conflict with jmorecfg.h header from libjpeg, so we have |
33 | // to make sure libjpeg won't try to define boolean itself. This is done by | |
34 | // defining HAVE_BOOLEAN. | |
6d3d756a | 35 | #if defined(__WXMSW__) && (defined(__MWERKS__) || defined(__DIGITALMARS__)) |
e7ca6139 | 36 | #define HAVE_BOOLEAN |
9ed0d735 | 37 | #include "wx/msw/wrapwin.h" |
e7ca6139 | 38 | #endif |
cb69afe0 | 39 | |
995612e2 VZ |
40 | extern "C" |
41 | { | |
cd2a4e16 JS |
42 | #if defined(__WXMSW__) |
43 | #define XMD_H | |
44 | #endif | |
995612e2 | 45 | #include "jpeglib.h" |
e9c4b1a2 | 46 | } |
cb69afe0 | 47 | |
e9c4b1a2 JS |
48 | #include "wx/filefn.h" |
49 | #include "wx/wfstream.h" | |
e9c4b1a2 JS |
50 | #include "wx/module.h" |
51 | ||
52 | // For memcpy | |
53 | #include <string.h> | |
b59ff3c9 VS |
54 | // For JPEG library error handling |
55 | #include <setjmp.h> | |
e9c4b1a2 JS |
56 | |
57 | #ifdef __SALFORDC__ | |
e9c4b1a2 JS |
58 | #undef FAR |
59 | #endif | |
e9c4b1a2 | 60 | |
d7c42914 VZ |
61 | // ---------------------------------------------------------------------------- |
62 | // types | |
63 | // ---------------------------------------------------------------------------- | |
64 | ||
65 | // the standard definition of METHODDEF(type) from jmorecfg.h is "static type" | |
66 | // which means that we can't declare the method functions as extern "C" - the | |
67 | // compiler (rightfully) complains about the multiple storage classes in | |
68 | // declaration | |
69 | // | |
70 | // so we only add extern "C" when using our own, modified, jmorecfg.h - and use | |
71 | // whatever we have in the system headers if this is what we use hoping that it | |
72 | // should be ok (can't do anything else) | |
73 | #ifdef JPEG_METHOD_LINKAGE | |
74 | #define CPP_METHODDEF(type) extern "C" METHODDEF(type) | |
75 | #else // not using our jmorecfg.h header | |
76 | #define CPP_METHODDEF(type) METHODDEF(type) | |
77 | #endif | |
90350682 | 78 | |
e9c4b1a2 JS |
79 | //----------------------------------------------------------------------------- |
80 | // wxJPEGHandler | |
81 | //----------------------------------------------------------------------------- | |
82 | ||
e9c4b1a2 | 83 | IMPLEMENT_DYNAMIC_CLASS(wxJPEGHandler,wxImageHandler) |
e9c4b1a2 | 84 | |
9ab6ee85 GRG |
85 | #if wxUSE_STREAMS |
86 | ||
e9c4b1a2 JS |
87 | //------------- JPEG Data Source Manager |
88 | ||
1aaaa712 VS |
89 | #define JPEG_IO_BUFFER_SIZE 2048 |
90 | ||
e9c4b1a2 JS |
91 | typedef struct { |
92 | struct jpeg_source_mgr pub; /* public fields */ | |
995612e2 | 93 | |
e9c4b1a2 | 94 | JOCTET* buffer; /* start of buffer */ |
1aaaa712 | 95 | wxInputStream *stream; |
e9b964cf | 96 | } wx_source_mgr; |
e9c4b1a2 | 97 | |
e9b964cf | 98 | typedef wx_source_mgr * wx_src_ptr; |
e9c4b1a2 | 99 | |
e9b964cf | 100 | CPP_METHODDEF(void) wx_init_source ( j_decompress_ptr WXUNUSED(cinfo) ) |
e9c4b1a2 JS |
101 | { |
102 | } | |
103 | ||
e9b964cf | 104 | CPP_METHODDEF(boolean) wx_fill_input_buffer ( j_decompress_ptr cinfo ) |
e9c4b1a2 | 105 | { |
e9b964cf | 106 | wx_src_ptr src = (wx_src_ptr) cinfo->src; |
1aaaa712 VS |
107 | |
108 | src->pub.next_input_byte = src->buffer; | |
109 | src->pub.bytes_in_buffer = src->stream->Read(src->buffer, JPEG_IO_BUFFER_SIZE).LastRead(); | |
110 | ||
111 | if (src->pub.bytes_in_buffer == 0) // check for end-of-stream | |
112 | { | |
113 | // Insert a fake EOI marker | |
114 | src->buffer[0] = 0xFF; | |
115 | src->buffer[1] = JPEG_EOI; | |
116 | src->pub.bytes_in_buffer = 2; | |
117 | } | |
e9c4b1a2 JS |
118 | return TRUE; |
119 | } | |
120 | ||
e9b964cf | 121 | CPP_METHODDEF(void) wx_skip_input_data ( j_decompress_ptr cinfo, long num_bytes ) |
e9c4b1a2 | 122 | { |
1aaaa712 VS |
123 | if (num_bytes > 0) |
124 | { | |
e9b964cf | 125 | wx_src_ptr src = (wx_src_ptr) cinfo->src; |
1aaaa712 | 126 | |
33ac7e6f | 127 | while (num_bytes > (long)src->pub.bytes_in_buffer) |
1aaaa712 VS |
128 | { |
129 | num_bytes -= (long) src->pub.bytes_in_buffer; | |
130 | src->pub.fill_input_buffer(cinfo); | |
131 | } | |
132 | src->pub.next_input_byte += (size_t) num_bytes; | |
133 | src->pub.bytes_in_buffer -= (size_t) num_bytes; | |
134 | } | |
e9c4b1a2 JS |
135 | } |
136 | ||
e9b964cf | 137 | CPP_METHODDEF(void) wx_term_source ( j_decompress_ptr cinfo ) |
e9c4b1a2 | 138 | { |
e9b964cf | 139 | wx_src_ptr src = (wx_src_ptr) cinfo->src; |
995612e2 | 140 | |
1aaaa712 | 141 | if (src->pub.bytes_in_buffer > 0) |
3ca6a5f0 | 142 | src->stream->SeekI(-(long)src->pub.bytes_in_buffer, wxFromCurrent); |
1aaaa712 | 143 | delete[] src->buffer; |
e9c4b1a2 JS |
144 | } |
145 | ||
e9c4b1a2 | 146 | |
b59ff3c9 VS |
147 | // JPEG error manager: |
148 | ||
e9b964cf | 149 | struct wx_error_mgr { |
995612e2 | 150 | struct jpeg_error_mgr pub; /* "public" fields */ |
b59ff3c9 | 151 | |
995612e2 | 152 | jmp_buf setjmp_buffer; /* for return to caller */ |
b59ff3c9 VS |
153 | }; |
154 | ||
e9b964cf | 155 | typedef struct wx_error_mgr * wx_error_ptr; |
b59ff3c9 VS |
156 | |
157 | /* | |
158 | * Here's the routine that will replace the standard error_exit method: | |
159 | */ | |
160 | ||
e9b964cf | 161 | CPP_METHODDEF(void) wx_error_exit (j_common_ptr cinfo) |
b59ff3c9 | 162 | { |
e9b964cf VS |
163 | /* cinfo->err really points to a wx_error_mgr struct, so coerce pointer */ |
164 | wx_error_ptr myerr = (wx_error_ptr) cinfo->err; | |
b59ff3c9 VS |
165 | |
166 | /* Always display the message. */ | |
167 | /* We could postpone this until after returning, if we chose. */ | |
ef25e5a4 | 168 | (*cinfo->err->output_message) (cinfo); |
b59ff3c9 VS |
169 | |
170 | /* Return control to the setjmp point */ | |
171 | longjmp(myerr->setjmp_buffer, 1); | |
172 | } | |
173 | ||
ef25e5a4 VZ |
174 | /* |
175 | * This will replace the standard output_message method when the user | |
176 | * wants us to be silent (verbose==false). We must have such method instead of | |
177 | * simply using NULL for cinfo->err->output_message because it's called | |
178 | * unconditionally from within libjpeg when there's "garbage input". | |
179 | */ | |
180 | CPP_METHODDEF(void) wx_ignore_message (j_common_ptr WXUNUSED(cinfo)) | |
181 | { | |
182 | } | |
183 | ||
e9b964cf | 184 | void wx_jpeg_io_src( j_decompress_ptr cinfo, wxInputStream& infile ) |
90350682 | 185 | { |
e9b964cf | 186 | wx_src_ptr src; |
90350682 VZ |
187 | |
188 | if (cinfo->src == NULL) { /* first time for this JPEG object? */ | |
189 | cinfo->src = (struct jpeg_source_mgr *) | |
190 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, | |
e9b964cf | 191 | sizeof(wx_source_mgr)); |
90350682 | 192 | } |
e9b964cf | 193 | src = (wx_src_ptr) cinfo->src; |
90350682 VZ |
194 | src->pub.bytes_in_buffer = 0; /* forces fill_input_buffer on first read */ |
195 | src->buffer = new JOCTET[JPEG_IO_BUFFER_SIZE]; | |
196 | src->pub.next_input_byte = NULL; /* until buffer loaded */ | |
197 | src->stream = &infile; | |
198 | ||
e9b964cf VS |
199 | src->pub.init_source = wx_init_source; |
200 | src->pub.fill_input_buffer = wx_fill_input_buffer; | |
201 | src->pub.skip_input_data = wx_skip_input_data; | |
90350682 | 202 | src->pub.resync_to_restart = jpeg_resync_to_restart; /* use default method */ |
e9b964cf | 203 | src->pub.term_source = wx_term_source; |
90350682 VZ |
204 | } |
205 | ||
206 | ||
3ca6a5f0 BP |
207 | // temporarily disable the warning C4611 (interaction between '_setjmp' and |
208 | // C++ object destruction is non-portable) - I don't see any dtors here | |
209 | #ifdef __VISUALC__ | |
210 | #pragma warning(disable:4611) | |
211 | #endif /* VC++ */ | |
e9c4b1a2 | 212 | |
700ec454 | 213 | bool wxJPEGHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose, int WXUNUSED(index) ) |
e9c4b1a2 JS |
214 | { |
215 | struct jpeg_decompress_struct cinfo; | |
e9b964cf | 216 | struct wx_error_mgr jerr; |
e9c4b1a2 JS |
217 | JSAMPARRAY tempbuf; |
218 | unsigned char *ptr; | |
219 | unsigned stride; | |
995612e2 | 220 | |
e9c4b1a2 | 221 | image->Destroy(); |
b59ff3c9 | 222 | cinfo.err = jpeg_std_error( &jerr.pub ); |
e9b964cf | 223 | jerr.pub.error_exit = wx_error_exit; |
b59ff3c9 | 224 | |
ef25e5a4 VZ |
225 | if (!verbose) |
226 | cinfo.err->output_message = wx_ignore_message; | |
deb2fec0 | 227 | |
e9b964cf | 228 | /* Establish the setjmp return context for wx_error_exit to use. */ |
b59ff3c9 VS |
229 | if (setjmp(jerr.setjmp_buffer)) { |
230 | /* If we get here, the JPEG code has signaled an error. | |
231 | * We need to clean up the JPEG object, close the input file, and return. | |
232 | */ | |
33ac7e6f | 233 | if (verbose) |
58c837a4 | 234 | wxLogError(_("JPEG: Couldn't load - file is probably corrupted.")); |
192644bf | 235 | (cinfo.src->term_source)(&cinfo); |
b59ff3c9 VS |
236 | jpeg_destroy_decompress(&cinfo); |
237 | if (image->Ok()) image->Destroy(); | |
7beb59f3 | 238 | return false; |
b59ff3c9 VS |
239 | } |
240 | ||
e9c4b1a2 | 241 | jpeg_create_decompress( &cinfo ); |
e9b964cf | 242 | wx_jpeg_io_src( &cinfo, stream ); |
e9c4b1a2 JS |
243 | jpeg_read_header( &cinfo, TRUE ); |
244 | cinfo.out_color_space = JCS_RGB; | |
245 | jpeg_start_decompress( &cinfo ); | |
995612e2 | 246 | |
e9c4b1a2 JS |
247 | image->Create( cinfo.image_width, cinfo.image_height ); |
248 | if (!image->Ok()) { | |
249 | jpeg_finish_decompress( &cinfo ); | |
250 | jpeg_destroy_decompress( &cinfo ); | |
7beb59f3 | 251 | return false; |
e9c4b1a2 | 252 | } |
7beb59f3 | 253 | image->SetMask( false ); |
e9c4b1a2 JS |
254 | ptr = image->GetData(); |
255 | stride = cinfo.output_width * 3; | |
256 | tempbuf = (*cinfo.mem->alloc_sarray) | |
257 | ((j_common_ptr) &cinfo, JPOOL_IMAGE, stride, 1 ); | |
995612e2 | 258 | |
e9c4b1a2 JS |
259 | while ( cinfo.output_scanline < cinfo.output_height ) { |
260 | jpeg_read_scanlines( &cinfo, tempbuf, 1 ); | |
261 | memcpy( ptr, tempbuf[0], stride ); | |
262 | ptr += stride; | |
263 | } | |
264 | jpeg_finish_decompress( &cinfo ); | |
265 | jpeg_destroy_decompress( &cinfo ); | |
7beb59f3 | 266 | return true; |
e9c4b1a2 JS |
267 | } |
268 | ||
e9c4b1a2 JS |
269 | typedef struct { |
270 | struct jpeg_destination_mgr pub; | |
995612e2 | 271 | |
e9c4b1a2 JS |
272 | wxOutputStream *stream; |
273 | JOCTET * buffer; | |
e9b964cf | 274 | } wx_destination_mgr; |
e9c4b1a2 | 275 | |
e9b964cf | 276 | typedef wx_destination_mgr * wx_dest_ptr; |
e9c4b1a2 | 277 | |
995612e2 | 278 | #define OUTPUT_BUF_SIZE 4096 /* choose an efficiently fwrite'able size */ |
e9c4b1a2 | 279 | |
e9b964cf | 280 | CPP_METHODDEF(void) wx_init_destination (j_compress_ptr cinfo) |
e9c4b1a2 | 281 | { |
e9b964cf | 282 | wx_dest_ptr dest = (wx_dest_ptr) cinfo->dest; |
995612e2 | 283 | |
e9c4b1a2 JS |
284 | /* Allocate the output buffer --- it will be released when done with image */ |
285 | dest->buffer = (JOCTET *) | |
286 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
287 | OUTPUT_BUF_SIZE * sizeof(JOCTET)); | |
288 | dest->pub.next_output_byte = dest->buffer; | |
289 | dest->pub.free_in_buffer = OUTPUT_BUF_SIZE; | |
290 | } | |
291 | ||
e9b964cf | 292 | CPP_METHODDEF(boolean) wx_empty_output_buffer (j_compress_ptr cinfo) |
e9c4b1a2 | 293 | { |
e9b964cf | 294 | wx_dest_ptr dest = (wx_dest_ptr) cinfo->dest; |
995612e2 | 295 | |
e9c4b1a2 JS |
296 | dest->stream->Write(dest->buffer, OUTPUT_BUF_SIZE); |
297 | dest->pub.next_output_byte = dest->buffer; | |
298 | dest->pub.free_in_buffer = OUTPUT_BUF_SIZE; | |
299 | return TRUE; | |
300 | } | |
301 | ||
e9b964cf | 302 | CPP_METHODDEF(void) wx_term_destination (j_compress_ptr cinfo) |
e9c4b1a2 | 303 | { |
e9b964cf | 304 | wx_dest_ptr dest = (wx_dest_ptr) cinfo->dest; |
e9c4b1a2 JS |
305 | size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer; |
306 | /* Write any data remaining in the buffer */ | |
307 | if (datacount > 0) | |
308 | dest->stream->Write(dest->buffer, datacount); | |
309 | } | |
310 | ||
e9b964cf | 311 | GLOBAL(void) wx_jpeg_io_dest (j_compress_ptr cinfo, wxOutputStream& outfile) |
e9c4b1a2 | 312 | { |
e9b964cf | 313 | wx_dest_ptr dest; |
995612e2 VZ |
314 | |
315 | if (cinfo->dest == NULL) { /* first time for this JPEG object? */ | |
e9c4b1a2 JS |
316 | cinfo->dest = (struct jpeg_destination_mgr *) |
317 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, | |
e9b964cf | 318 | sizeof(wx_destination_mgr)); |
e9c4b1a2 | 319 | } |
995612e2 | 320 | |
e9b964cf VS |
321 | dest = (wx_dest_ptr) cinfo->dest; |
322 | dest->pub.init_destination = wx_init_destination; | |
323 | dest->pub.empty_output_buffer = wx_empty_output_buffer; | |
324 | dest->pub.term_destination = wx_term_destination; | |
e9c4b1a2 JS |
325 | dest->stream = &outfile; |
326 | } | |
327 | ||
deb2fec0 | 328 | bool wxJPEGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbose ) |
e9c4b1a2 JS |
329 | { |
330 | struct jpeg_compress_struct cinfo; | |
e9b964cf | 331 | struct wx_error_mgr jerr; |
995612e2 | 332 | JSAMPROW row_pointer[1]; /* pointer to JSAMPLE row[s] */ |
e9c4b1a2 | 333 | JSAMPLE *image_buffer; |
995612e2 VZ |
334 | int stride; /* physical row width in image buffer */ |
335 | ||
b59ff3c9 | 336 | cinfo.err = jpeg_std_error(&jerr.pub); |
e9b964cf | 337 | jerr.pub.error_exit = wx_error_exit; |
b59ff3c9 | 338 | |
ef25e5a4 VZ |
339 | if (!verbose) |
340 | cinfo.err->output_message = wx_ignore_message; | |
deb2fec0 | 341 | |
e9b964cf | 342 | /* Establish the setjmp return context for wx_error_exit to use. */ |
33ac7e6f | 343 | if (setjmp(jerr.setjmp_buffer)) |
58c837a4 RR |
344 | { |
345 | /* If we get here, the JPEG code has signaled an error. | |
346 | * We need to clean up the JPEG object, close the input file, and return. | |
347 | */ | |
33ac7e6f | 348 | if (verbose) |
58c837a4 RR |
349 | wxLogError(_("JPEG: Couldn't save image.")); |
350 | jpeg_destroy_compress(&cinfo); | |
7beb59f3 | 351 | return false; |
b59ff3c9 VS |
352 | } |
353 | ||
e9c4b1a2 | 354 | jpeg_create_compress(&cinfo); |
e9b964cf | 355 | wx_jpeg_io_dest(&cinfo, stream); |
995612e2 | 356 | |
e9c4b1a2 JS |
357 | cinfo.image_width = image->GetWidth(); |
358 | cinfo.image_height = image->GetHeight(); | |
359 | cinfo.input_components = 3; | |
360 | cinfo.in_color_space = JCS_RGB; | |
361 | jpeg_set_defaults(&cinfo); | |
5e5437e0 JS |
362 | |
363 | // TODO: 3rd parameter is force_baseline, what value should this be? | |
364 | // Code says: "If force_baseline is TRUE, the computed quantization table entries | |
365 | // are limited to 1..255 for JPEG baseline compatibility." | |
366 | // 'Quality' is a number between 0 (terrible) and 100 (very good). | |
367 | // The default (in jcparam.c, jpeg_set_defaults) is 75, | |
368 | // and force_baseline is TRUE. | |
9a679df6 JS |
369 | if (image->HasOption(wxIMAGE_OPTION_QUALITY)) |
370 | jpeg_set_quality(&cinfo, image->GetOptionInt(wxIMAGE_OPTION_QUALITY), TRUE); | |
5e5437e0 | 371 | |
fe9308c6 VZ |
372 | // set the resolution fields in the output file |
373 | UINT16 resX, | |
374 | resY; | |
375 | if ( image->HasOption(wxIMAGE_OPTION_RESOLUTIONX) && | |
376 | image->HasOption(wxIMAGE_OPTION_RESOLUTIONY) ) | |
89d38f8c | 377 | { |
4c2740ec WS |
378 | resX = (UINT16)image->GetOptionInt(wxIMAGE_OPTION_RESOLUTIONX); |
379 | resY = (UINT16)image->GetOptionInt(wxIMAGE_OPTION_RESOLUTIONY); | |
fe9308c6 VZ |
380 | } |
381 | else if ( image->HasOption(wxIMAGE_OPTION_RESOLUTION) ) | |
382 | { | |
383 | resX = | |
4c2740ec | 384 | resY = (UINT16)image->GetOptionInt(wxIMAGE_OPTION_RESOLUTION); |
fe9308c6 VZ |
385 | } |
386 | else | |
387 | { | |
388 | resX = | |
389 | resY = 0; | |
390 | } | |
391 | ||
392 | if ( resX && resY ) | |
393 | { | |
394 | cinfo.X_density = resX; | |
395 | cinfo.Y_density = resY; | |
89d38f8c VS |
396 | } |
397 | ||
398 | // sets the resolution unit field in the output file | |
399 | // wxIMAGE_RESOLUTION_INCHES for inches | |
400 | // wxIMAGE_RESOLUTION_CM for centimeters | |
fe9308c6 | 401 | if ( image->HasOption(wxIMAGE_OPTION_RESOLUTIONUNIT) ) |
89d38f8c | 402 | { |
7ac31c42 | 403 | cinfo.density_unit = (UINT8)image->GetOptionInt(wxIMAGE_OPTION_RESOLUTIONUNIT); |
89d38f8c VS |
404 | } |
405 | ||
e9c4b1a2 | 406 | jpeg_start_compress(&cinfo, TRUE); |
995612e2 VZ |
407 | |
408 | stride = cinfo.image_width * 3; /* JSAMPLEs per row in image_buffer */ | |
e9c4b1a2 JS |
409 | image_buffer = image->GetData(); |
410 | while (cinfo.next_scanline < cinfo.image_height) { | |
411 | row_pointer[0] = &image_buffer[cinfo.next_scanline * stride]; | |
412 | jpeg_write_scanlines( &cinfo, row_pointer, 1 ); | |
413 | } | |
414 | jpeg_finish_compress(&cinfo); | |
415 | jpeg_destroy_compress(&cinfo); | |
995612e2 | 416 | |
7beb59f3 | 417 | return true; |
e9c4b1a2 | 418 | } |
e9c4b1a2 | 419 | |
3ca6a5f0 BP |
420 | #ifdef __VISUALC__ |
421 | #pragma warning(default:4611) | |
422 | #endif /* VC++ */ | |
0828c087 | 423 | |
995612e2 | 424 | bool wxJPEGHandler::DoCanRead( wxInputStream& stream ) |
0828c087 VS |
425 | { |
426 | unsigned char hdr[2]; | |
995612e2 | 427 | |
79fa2374 | 428 | if ( !stream.Read(hdr, WXSIZEOF(hdr)) ) |
7beb59f3 | 429 | return false; |
79fa2374 | 430 | |
79fa2374 | 431 | return hdr[0] == 0xFF && hdr[1] == 0xD8; |
0828c087 VS |
432 | } |
433 | ||
9ab6ee85 GRG |
434 | #endif // wxUSE_STREAMS |
435 | ||
436 | #endif // wxUSE_LIBJPEG |