added support for reading resolution information from TIFF, JPEG and BMP formats; corrected some bugs with saving resolution; added command allowing to see the image resolution (if available) to the sample (heavily modified patch 1790546)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@48612 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -180,6 +180,7 @@ All (GUI):
 - Added wxToolTip::SetAutoPop() and SetReshow() (Jan Knepper)
 - Added wxTaskBarIcon::Destroy()
 - Added XRC handler for wxSearchCtrl (Sander Berents)
+- Read image resolution from TIFF, JPEG and BMP images (Maycon Aparecido Gasoto)
 
 wxGTK:
 

samples/image/image.cpp

@@ -118,6 +118,7 @@ public:
 
     void OnAbout( wxCommandEvent &event );
     void OnNewFrame( wxCommandEvent &event );
+    void OnImageInfo( wxCommandEvent &event );
 #ifdef wxHAVE_RAW_BITMAP
     void OnTestRawBitmap( wxCommandEvent &event );
 #endif // wxHAVE_RAW_BITMAP
@@ -131,6 +132,13 @@ public:
     MyCanvas         *m_canvas;
 
 private:
+    // ask user for the file name and try to load an image from it
+    //
+    // return the file path on success, empty string if we failed to load the
+    // image or were cancelled by user
+    static wxString LoadUserImage(wxImage& image);
+
+
     DECLARE_DYNAMIC_CLASS(MyFrame)
     DECLARE_EVENT_TABLE()
 };
@@ -1101,17 +1109,19 @@ enum
     ID_QUIT  = wxID_EXIT,
     ID_ABOUT = wxID_ABOUT,
     ID_NEW = 100,
-    ID_SHOWRAW = 101
+    ID_INFO,
+    ID_SHOWRAW
 };
 
 IMPLEMENT_DYNAMIC_CLASS( MyFrame, wxFrame )
 
-BEGIN_EVENT_TABLE(MyFrame,wxFrame)
+BEGIN_EVENT_TABLE(MyFrame, wxFrame)
   EVT_MENU    (ID_ABOUT, MyFrame::OnAbout)
   EVT_MENU    (ID_QUIT,  MyFrame::OnQuit)
-  EVT_MENU    (ID_NEW,  MyFrame::OnNewFrame)
+  EVT_MENU    (ID_NEW,   MyFrame::OnNewFrame)
+  EVT_MENU    (ID_INFO,  MyFrame::OnImageInfo)
 #ifdef wxHAVE_RAW_BITMAP
-  EVT_MENU    (ID_SHOWRAW,  MyFrame::OnTestRawBitmap)
+  EVT_MENU    (ID_SHOWRAW, MyFrame::OnTestRawBitmap)
 #endif
 
 #if wxUSE_CLIPBOARD
@@ -1128,8 +1138,9 @@ MyFrame::MyFrame()
 
   wxMenu *menuImage = new wxMenu;
   menuImage->Append( ID_NEW, _T("&Show any image...\tCtrl-O"));
-
+  menuImage->Append( ID_INFO, _T("Show image &information...\tCtrl-I"));
 #ifdef wxHAVE_RAW_BITMAP
+  menuImage->AppendSeparator();
   menuImage->Append( ID_SHOWRAW, _T("Test &raw bitmap...\tCtrl-R"));
 #endif
   menuImage->AppendSeparator();
@@ -1171,23 +1182,71 @@ void MyFrame::OnAbout( wxCommandEvent &WXUNUSED(event) )
                       _T("About wxImage Demo"), wxICON_INFORMATION | wxOK );
 }
 
+wxString MyFrame::LoadUserImage(wxImage& image)
+{
+    wxString filename;
+
+#if wxUSE_FILEDLG
+    filename = wxFileSelector(_T("Select image file"));
+    if ( !filename.empty() )
+    {
+        if ( !image.LoadFile(filename) )
+        {
+            wxLogError(_T("Couldn't load image from '%s'."), filename.c_str());
+
+            return wxEmptyString;
+        }
+    }
+#endif // wxUSE_FILEDLG
+
+    return filename;
+}
+
 void MyFrame::OnNewFrame( wxCommandEvent &WXUNUSED(event) )
 {
-#if wxUSE_FILEDLG
-    wxString filename = wxFileSelector(_T("Select image file"));
-    if ( !filename )
-        return;
-
     wxImage image;
-    if ( !image.LoadFile(filename) )
+    wxString filename = LoadUserImage(image);
+    if ( !filename.empty() )
+        (new MyImageFrame(this, filename, wxBitmap(image)))->Show();
+}
+
+void MyFrame::OnImageInfo( wxCommandEvent &WXUNUSED(event) )
+{
+    wxImage image;
+    if ( !LoadUserImage(image).empty() )
     {
-        wxLogError(_T("Couldn't load image from '%s'."), filename.c_str());
+        // TODO: show more information about the file
+        wxString info = wxString::Format("Image size: %dx%d",
+                                         image.GetWidth(),
+                                         image.GetHeight());
 
-        return;
+        int xres = image.GetOptionInt(wxIMAGE_OPTION_RESOLUTIONX),
+            yres = image.GetOptionInt(wxIMAGE_OPTION_RESOLUTIONY);
+        if ( xres || yres )
+        {
+            info += wxString::Format("\nResolution: %dx%d", xres, yres);
+            switch ( image.GetOptionInt(wxIMAGE_OPTION_RESOLUTIONUNIT) )
+            {
+                default:
+                    wxFAIL_MSG( "unknown image resolution units" );
+                    // fall through
+
+                case wxIMAGE_RESOLUTION_NONE:
+                    info += " in default units";
+                    break;
+
+                case wxIMAGE_RESOLUTION_INCHES:
+                    info += " in";
+                    break;
+
+                case wxIMAGE_RESOLUTION_CM:
+                    info += " cm";
+                    break;
+            }
+        }
+
+        wxLogMessage("%s", info);
     }
-
-    (new MyImageFrame(this, filename, wxBitmap(image)))->Show();
-#endif // wxUSE_FILEDLG
 }
 
 #ifdef wxHAVE_RAW_BITMAP

src/common/imagbmp.cpp

@@ -27,6 +27,7 @@
     #include "wx/bitmap.h"
     #include "wx/palette.h"
     #include "wx/intl.h"
+    #include "wx/math.h"
 #endif
 
 #include "wx/filefn.h"
@@ -154,7 +155,7 @@ bool wxBMPHandler::SaveDib(wxImage *image,
         wxUint16  bpp;            // bits per pixel
         wxUint32  compression;    // compression method
         wxUint32  size_of_bmp;    // size of the bitmap
-        wxUint32  h_res, v_res;   // image resolution in dpi
+        wxUint32  h_res, v_res;   // image resolution in pixels-per-meter
         wxUint32  num_clrs;       // number of colors used
         wxUint32  num_signif_clrs;// number of significant colors
     } hdr;
@@ -181,7 +182,37 @@ bool wxBMPHandler::SaveDib(wxImage *image,
     hdr.bpp = wxUINT16_SWAP_ON_BE(bpp);
     hdr.compression = 0; // RGB uncompressed
     hdr.size_of_bmp = wxUINT32_SWAP_ON_BE(row_width * image->GetHeight());
-    hdr.h_res = hdr.v_res = wxUINT32_SWAP_ON_BE(72);  // 72dpi is standard
+
+    // get the resolution from the image options  or fall back to 72dpi standard
+    // for the BMP format if not specified
+    wxUint32 hres = image->GetOptionInt(wxIMAGE_OPTION_RESOLUTIONX),
+             vres = image->GetOptionInt(wxIMAGE_OPTION_RESOLUTIONY);
+    switch ( image->GetOptionInt(wxIMAGE_OPTION_RESOLUTION) )
+    {
+        default:
+            wxFAIL_MSG( _T("unexpected image resolution units") );
+            // fall through
+
+        case wxIMAGE_RESOLUTION_NONE:
+            hres =
+            vres = 72;
+            // fall through to convert it to correct units
+
+        case wxIMAGE_RESOLUTION_INCHES:
+            // convert resolution in inches to resolution in centimeters
+            hres *= 100*mm2inches;
+            vres *= 100*mm2inches;
+            // fall through to convert it to resolution in meters
+
+        case wxIMAGE_RESOLUTION_CM:
+            // convert resolution in centimeters to resolution in meters
+            hres *= 100;
+            vres *= 100;
+            break;
+    }
+
+    hdr.h_res = wxUINT32_SWAP_ON_BE(hres);
+    hdr.v_res = wxUINT32_SWAP_ON_BE(vres);
     hdr.num_clrs = wxUINT32_SWAP_ON_BE(palette_size); // # colors in colormap
     hdr.num_signif_clrs = 0;     // all colors are significant
 
@@ -906,6 +937,7 @@ bool wxBMPHandler::LoadDib(wxImage *image, wxInputStream& stream,
     }
 
     stream.Read(dbuf, 4 * 2);
+
     int ncolors = wxINT32_SWAP_ON_BE( (int)dbuf[0] );
     if (ncolors == 0)
         ncolors = 1 << bpp;
@@ -944,6 +976,11 @@ bool wxBMPHandler::LoadDib(wxImage *image, wxInputStream& stream,
 
     }
 
+    // the resolution in the bitmap header is in meters, convert to centimeters
+    image->SetOption(wxIMAGE_OPTION_RESOLUTIONUNIT, wxIMAGE_RESOLUTION_CM);
+    image->SetOption(wxIMAGE_OPTION_RESOLUTIONX, dbuf[2]/100);
+    image->SetOption(wxIMAGE_OPTION_RESOLUTIONY, dbuf[3]/100);
+
     return true;
 }
 

src/common/imagjpeg.cpp

@@ -310,6 +310,17 @@ bool wxJPEGHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbos
         }
     }
 
+    // set up resolution if available: it's part of optional JFIF APP0 chunk
+    if ( cinfo.saw_JFIF_marker )
+    {
+        image->SetOption(wxIMAGE_OPTION_RESOLUTIONX, cinfo.X_density);
+        image->SetOption(wxIMAGE_OPTION_RESOLUTIONY, cinfo.Y_density);
+
+        // we use the same values for this option as libjpeg so we don't need
+        // any conversion here
+        image->SetOption(wxIMAGE_OPTION_RESOLUTIONUNIT, cinfo.density_unit);
+    }
+
     jpeg_finish_decompress( &cinfo );
     jpeg_destroy_decompress( &cinfo );
     return true;

src/common/imagtiff.cpp

@@ -344,6 +344,43 @@ bool wxTIFFHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbos
             alpha -= 2*w;
     }
 
+    // set the image resolution if it's available
+    uint16 tiffRes;
+    if ( TIFFGetField(tif, TIFFTAG_RESOLUTIONUNIT, &tiffRes) )
+    {
+        wxImageResolution res;
+        switch ( tiffRes )
+        {
+            default:
+                wxLogWarning(_("Unknown TIFF resolution unit %d ignored"),
+                             tiffRes);
+                // fall through
+
+            case RESUNIT_NONE:
+                res = wxIMAGE_RESOLUTION_NONE;
+                break;
+
+            case RESUNIT_INCH:
+                res = wxIMAGE_RESOLUTION_INCHES;
+                break;
+
+            case RESUNIT_CENTIMETER:
+                res = wxIMAGE_RESOLUTION_CM;
+                break;
+        }
+
+        if ( res != wxIMAGE_RESOLUTION_NONE )
+        {
+            float xres, yres;
+            if ( TIFFGetField(tif, TIFFTAG_XRESOLUTION, &xres) )
+                image->SetOption(wxIMAGE_OPTION_RESOLUTIONX, xres);
+
+            if ( TIFFGetField(tif, TIFFTAG_YRESOLUTION, &yres) )
+                image->SetOption(wxIMAGE_OPTION_RESOLUTIONY, yres);
+        }
+    }
+
+
     _TIFFfree( raster );
 
     TIFFClose( tif );
@@ -386,22 +423,44 @@ bool wxTIFFHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbo
     TIFFSetField(tif, TIFFTAG_ORIENTATION, ORIENTATION_TOPLEFT);
     TIFFSetField(tif, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG);
 
-    if ( image->HasOption(wxIMAGE_OPTION_RESOLUTIONX) &&
+    // save the image resolution if we have it
-            image->HasOption(wxIMAGE_OPTION_RESOLUTIONY) )
+    int xres, yres;
+    const wxImageResolution res = GetResolutionFromOptions(*image, &xres, &yres);
+    uint16 tiffRes;
+    switch ( res )
     {
-        TIFFSetField(tif, TIFFTAG_XRESOLUTION,
+        default:
-                        (float)image->GetOptionInt(wxIMAGE_OPTION_RESOLUTIONX));
+            wxFAIL_MSG( _T("unknown image resolution units") );
-        TIFFSetField(tif, TIFFTAG_YRESOLUTION,
+            // fall through
-                        (float)image->GetOptionInt(wxIMAGE_OPTION_RESOLUTIONY));
+
+        case wxIMAGE_RESOLUTION_NONE:
+            tiffRes = RESUNIT_NONE;
+            break;
+
+        case wxIMAGE_RESOLUTION_INCHES:
+            tiffRes = RESUNIT_INCH;
+            break;
+
+        case wxIMAGE_RESOLUTION_CM:
+            tiffRes = RESUNIT_CENTIMETER;
+            break;
     }
 
+    if ( tiffRes != RESUNIT_NONE )
+    {
+        TIFFSetField(tif, TIFFTAG_RESOLUTIONUNIT, tiffRes);
+        TIFFSetField(tif, TIFFTAG_XRESOLUTION, (float)xres);
+        TIFFSetField(tif, TIFFTAG_YRESOLUTION, (float)yres);
+    }
+
+
     int spp = image->GetOptionInt(wxIMAGE_OPTION_SAMPLESPERPIXEL);
     if ( !spp )
         spp = 3;
 
     int bpp = image->GetOptionInt(wxIMAGE_OPTION_BITSPERSAMPLE);
     if ( !bpp )
-        bpp=8;
+        bpp = 8;
 
     int compression = image->GetOptionInt(wxIMAGE_OPTION_COMPRESSION);
     if ( !compression )