Merge master.

[dcpomatic.git] / src / lib / image.cc

diff --git a/src/lib/image.cc b/src/lib/image.cc
index b706f7fdc3f68fdcf7b611835631ce315eff016a..98645c2996a4219f02681d276090b737df66df4e 100644 (file)
--- a/src/lib/image.cc
+++ b/src/lib/image.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2012 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2012-2014 Carl Hetherington <cth@carlh.net>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -33,9 +33,12 @@ extern "C" {
 #include "scaler.h"
 #include "timer.h"
 
+#include "i18n.h"
+
 using std::string;
 using std::min;
 using std::cout;
+using std::cerr;
 using boost::shared_ptr;
 using dcp::Size;
 
@@ -89,26 +92,38 @@ Image::crop_scale_window (Crop crop, dcp::Size inter_size, dcp::Size out_size, S
        */
        assert (aligned ());
 
+       assert (out_size.width >= inter_size.width);
+       assert (out_size.height >= inter_size.height);
+
+       /* Here's an image of out_size */
        shared_ptr<Image> out (new Image (out_format, out_size, out_aligned));
        out->make_black ();
-       
-       dcp::Size cropped_size = crop.apply (size ());
 
+       /* Size of the image after any crop */
+       dcp::Size const cropped_size = crop.apply (size ());
+
+       /* Scale context for a scale from cropped_size to inter_size */
        struct SwsContext* scale_context = sws_getContext (
                        cropped_size.width, cropped_size.height, pixel_format(),
                        inter_size.width, inter_size.height, out_format,
                        scaler->ffmpeg_id (), 0, 0, 0
                );
 
+       if (!scale_context) {
+               throw StringError (N_("Could not allocate SwsContext"));
+       }
+
+       /* Prepare input data pointers with crop */
        uint8_t* scale_in_data[components()];
        for (int c = 0; c < components(); ++c) {
                scale_in_data[c] = data()[c] + int (rint (bytes_per_pixel(c) * crop.left)) + stride()[c] * (crop.top / line_factor(c));
        }
 
+       /* Corner of the image within out_size */
        Position<int> const corner ((out_size.width - inter_size.width) / 2, (out_size.height - inter_size.height) / 2);
 
-       uint8_t* scale_out_data[components()];
-       for (int c = 0; c < components(); ++c) {
+       uint8_t* scale_out_data[out->components()];
+       for (int c = 0; c < out->components(); ++c) {
                scale_out_data[c] = out->data()[c] + int (rint (out->bytes_per_pixel(c) * corner.x)) + out->stride()[c] * corner.y;
        }