X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/8529b0b909e478f0cf43aaafb262d1913d87c824..c81394808bf7efd84e4294e44a9a9a7b7f6dd8a9:/src/common/imagpng.cpp

diff --git a/src/common/imagpng.cpp b/src/common/imagpng.cpp
index 3472c5a1fc..5b151d568d 100644
--- a/src/common/imagpng.cpp
+++ b/src/common/imagpng.cpp
@@ -43,7 +43,7 @@
 // constants
 // ----------------------------------------------------------------------------
 
-// image can not have any transparent pixels at all, have only 100% opaque
+// image cannot have any transparent pixels at all, have only 100% opaque
 // and/or 100% transparent pixels in which case a simple mask is enough to
 // store this information in wxImage or have a real alpha channel in which case
 // we need to have it in wxImage as well
@@ -602,6 +602,47 @@ wxPNGHandler::LoadFile(wxImage *image,
     }
 #endif // wxUSE_PALETTE
 
+
+    // set the image resolution if it's available
+    png_uint_32 resX, resY;
+    int unitType;
+    if (png_get_pHYs(png_ptr, info_ptr, &resX, &resY, &unitType)
+        == PNG_INFO_pHYs)
+    {
+        wxImageResolution res = wxIMAGE_RESOLUTION_CM;
+
+        switch (unitType)
+        {
+            default:
+                wxLogWarning(_("Unknown PNG resolution unit %d"), unitType);
+                // fall through
+
+            case PNG_RESOLUTION_UNKNOWN:
+                image->SetOption(wxIMAGE_OPTION_RESOLUTIONX, resX);
+                image->SetOption(wxIMAGE_OPTION_RESOLUTIONY, resY);
+
+                res = wxIMAGE_RESOLUTION_NONE;
+                break;
+
+            case PNG_RESOLUTION_METER:
+                /*
+                Convert meters to centimeters.
+                Use a string to not lose precision (converting to cm and then
+                to inch would result in integer rounding error).
+                If an app wants an int, GetOptionInt will convert and round
+                down for them.
+                */
+                image->SetOption(wxIMAGE_OPTION_RESOLUTIONX,
+                    wxString::FromCDouble((double) resX / 100.0, 2));
+                image->SetOption(wxIMAGE_OPTION_RESOLUTIONY,
+                    wxString::FromCDouble((double) resY / 100.0, 2));
+                break;
+        }
+
+        image->SetOption(wxIMAGE_OPTION_RESOLUTIONUNIT, res);
+    }
+
+
     png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
 
     // loaded successfully, now init wxImage with this data