Attachment 408518 Details for Bug 150534

[patch] patch to read exif data (again)

xzgv-exif-orient.diff (text/plain), 2.45 KB, created by Harald Koenig on 2011-01-15 11:32:21 UTC

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Creator: Harald Koenig

Created: 2011-01-15 11:32:21 UTC

Size: 2.45 KB

patch

obsolete

>--- src/main.c~	2009-02-22 22:17:57.000000000 +0100
>+++ src/main.c	2011-01-15 12:23:25.000000000 +0100
>@@ -342,6 +342,118 @@
> }
> 
> 
>+static unsigned long read_tiff_long(FILE *in,int little_endian)
>+{
>+unsigned long ret;
>+
>+if(little_endian)
>+  {
>+  ret=fgetc(in);
>+  ret|=(fgetc(in)<<8);
>+  ret|=(fgetc(in)<<16);
>+  ret|=(fgetc(in)<<24);
>+  }
>+else
>+  {
>+  ret=(fgetc(in)<<24);
>+  ret|=(fgetc(in)<<16);
>+  ret|=(fgetc(in)<<8);
>+  ret|=fgetc(in);
>+  }
>+
>+return(ret);
>+}
>+
>+
>+static unsigned int read_tiff_short(FILE *in,int little_endian)
>+{
>+unsigned int ret;
>+
>+if(little_endian)
>+  {
>+  ret=fgetc(in);
>+  ret|=(fgetc(in)<<8);
>+  }
>+else
>+  {
>+  ret=(fgetc(in)<<8);
>+  ret|=fgetc(in);
>+  }
>+
>+return(ret);
>+}
>+
>+
>+int get_exif_orientation(char *filename)
>+{
>+static int xzgv_orient_lookup[]={0,1,3,2,7,4,6,5};
>+FILE *in;
>+unsigned char buf[4];
>+long ifd0_ofs;
>+int little_endian,f,num_ents;
>+int exif_orient;
>+
>+if((in=fopen(filename,"rb"))==NULL)
>+  return(0);
>+
>+fread(buf,1,4,in);
>+if(memcmp(buf,"\xff\xd8\xff\xe1",4)!=0)
>+  {
>+  fclose(in);
>+  return(0);
>+  }
>+
>+/* we can ignore data size */
>+fgetc(in);
>+fgetc(in);
>+
>+fread(buf,1,4,in);
>+if(memcmp(buf,"Exif",4)!=0 || fgetc(in) || fgetc(in))
>+  {
>+  fclose(in);
>+  return(0);
>+  }
>+
>+/* now at tiff header */
>+fread(buf,1,4,in);
>+if(memcmp(buf,"II*\0",4)!=0 && memcmp(buf,"MM\0*",4)!=0)
>+  {
>+  fclose(in);
>+  return(0);
>+  }
>+
>+little_endian=(memcmp(buf,"II*\0",4)==0);
>+
>+/* orientation is an IFD0 tag, so read IFD0 offset and seek */
>+ifd0_ofs=12+read_tiff_long(in,little_endian);
>+fseek(in,ifd0_ofs,SEEK_SET);
>+
>+/* search IFD0 for Orientation (0x112) */
>+exif_orient=-1;
>+num_ents=read_tiff_short(in,little_endian);
>+for(f=0;f<num_ents;f++)
>+  {
>+  fseek(in,ifd0_ofs+2+12*f,SEEK_SET);
>+  if(read_tiff_short(in,little_endian)==0x112 &&
>+     read_tiff_short(in,little_endian)==3 &&
>+     read_tiff_long(in,little_endian)==1)
>+    {
>+    exif_orient=read_tiff_short(in,little_endian);
>+    break;
>+    }
>+  }
>+
>+fclose(in);
>+
>+if(exif_orient<1 || exif_orient>8)
>+  return(0);
>+
>+/* return, converting Exif orientation to xzgv format */
>+
>+return(xzgv_orient_lookup[exif_orient-1]);
>+}
>+
>+
> /* small wrapper function for backend_create_image_from_file() which
>  * deals with mrf files and other oddities (currently GIF/PNG).
>  *
>@@ -359,6 +471,10 @@
> jpeg_exif_orient=0;
> 
> ret=backend_create_image_from_file(file);	/* use backend's loader */
>+
>+if(use_exif_orient)
>+  jpeg_exif_orient=get_exif_orientation(file);
>+
> origw=0; origh=0;
> if(ret)
>   {

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Attachments on bug 150534: 68395 | 408518 | 425443