LinGui: ensure loose crop always crops even values

Subsampled chroma (i.e. yuv420) requires that you do all cropping
on even boundaries and that the result has even dimensions.  There
were cases where my cropping could violate this.

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@4236 b64f7644-9d1e-0410-96f1-a4d463321fa5

diff --git a/gtk/src/hb-backend.c b/gtk/src/hb-backend.c
index e6021c41dd140dbb4be61869ce7ec0073a76e92b..400246f5f20b95e1fbc5933253e599a28b9cf485 100644 (file)
--- a/gtk/src/hb-backend.c
+++ b/gtk/src/hb-backend.c
@@ -3661,6 +3661,7 @@ ghb_set_scale(signal_user_data_t *ud, gint mode)
                keep_height = FALSE;
        }
        // Step needs to be at least 2 because odd widths cause scaler crash
+       // subsampled chroma requires even crop values.
        step = mod;
        widget = GHB_WIDGET (ud->builder, "scale_width");
        gtk_spin_button_set_increments (GTK_SPIN_BUTTON(widget), step, 16);
@@ -3680,13 +3681,13 @@ ghb_set_scale(signal_user_data_t *ud, gint mode)
        else
        {
                widget = GHB_WIDGET (ud->builder, "PictureTopCrop");
-               gtk_spin_button_set_increments (GTK_SPIN_BUTTON(widget), 1, 16);
+               gtk_spin_button_set_increments (GTK_SPIN_BUTTON(widget), 2, 16);
                widget = GHB_WIDGET (ud->builder, "PictureBottomCrop");
-               gtk_spin_button_set_increments (GTK_SPIN_BUTTON(widget), 1, 16);
+               gtk_spin_button_set_increments (GTK_SPIN_BUTTON(widget), 2, 16);
                widget = GHB_WIDGET (ud->builder, "PictureLeftCrop");
-               gtk_spin_button_set_increments (GTK_SPIN_BUTTON(widget), 1, 16);
+               gtk_spin_button_set_increments (GTK_SPIN_BUTTON(widget), 2, 16);
                widget = GHB_WIDGET (ud->builder, "PictureRightCrop");
-               gtk_spin_button_set_increments (GTK_SPIN_BUTTON(widget), 1, 16);
+               gtk_spin_button_set_increments (GTK_SPIN_BUTTON(widget), 2, 16);
        }
        ghb_title_info_t tinfo;
        ghb_get_title_info (&tinfo, titleindex);
@@ -3712,6 +3713,9 @@ ghb_set_scale(signal_user_data_t *ud, gint mode)
        {
                gint need1, need2;
 
+               // Note: until we allow color formats other than yuv420 in the
+               // pipeline, title width and height will always be even
+               //
                // Adjust the cropping to accomplish the desired width and height
                crop_width = tinfo.width - crop[2] - crop[3];
                crop_height = tinfo.height - crop[0] - crop[1];
@@ -3719,13 +3723,21 @@ ghb_set_scale(signal_user_data_t *ud, gint mode)
                height = MOD_DOWN(crop_height, mod);
 
                need1 = (crop_height - height) / 2;
+               // If the top crop would fall on an odd boundary, crop the extra
+               // line from the bottom
+               need1 &= ~0x01;
                need2 = crop_height - height - need1;
                crop[0] += need1;
                crop[1] += need2;
+
                need1 = (crop_width - width) / 2;
+               // If the top crop would fall on an odd boundary, crop the extra
+               // column from the right
+               need1 &= ~0x01;
                need2 = crop_width - width - need1;
                crop[2] += need1;
                crop[3] += need2;
+
                ghb_ui_update(ud, "PictureTopCrop", ghb_int64_value(crop[0]));
                ghb_ui_update(ud, "PictureBottomCrop", ghb_int64_value(crop[1]));
                ghb_ui_update(ud, "PictureLeftCrop", ghb_int64_value(crop[2]));