[lasem] render: export area selection support

[Emmanuel Pacaud <emmanuel src gnome org>]

commit 555b239efec5fa72e5bfa7a80843c9b2643b3552
Author: Emmanuel Pacaud <emmanuel gnome org>
Date:   Mon Jul 4 21:35:15 2016 +0200

    render: export area selection support
    
    Through the use of --size and --offset opions.

 src/lasemrender.c |   58 ++++++++++++++++++++++++++++++++++++++++++++++++----
 1 files changed, 53 insertions(+), 5 deletions(-)
---
diff --git a/src/lasemrender.c b/src/lasemrender.c
index f797277..8d769d8 100644
--- a/src/lasemrender.c
+++ b/src/lasemrender.c
@@ -41,6 +41,8 @@ static char *option_output_file_format = NULL;
 static char **option_input_filenames = NULL;
 static char *option_output_filename = NULL;
 static char *option_element_id = NULL;
+static char *option_offset = NULL;
+static char *option_size = NULL;
 double option_ppi = 72.0;
 double option_zoom = 1.0;
 
@@ -74,6 +76,10 @@ static const GOptionEntry entries[] =
                &option_zoom,                   N_("Zoom"), NULL },
        { "id",                 'i', 0, G_OPTION_ARG_STRING,
                &option_element_id,             N_("Element id"), NULL },
+       { "offset",             't', 0, G_OPTION_ARG_STRING,
+               &option_offset,                 N_("Offset"), NULL },
+       { "size",               's', 0, G_OPTION_ARG_STRING,
+               &option_size,           N_("Size"), NULL },
        { "debug",              'd', 0, G_OPTION_ARG_STRING,
                &option_debug_domains,          N_("Debug domains"), NULL },
        { NULL }
@@ -125,8 +131,11 @@ main(int argc, char **argv)
        FileFormat format;
        char *output_filename;
        char *input_filename;
+       double offset_x_pt, offset_y_pt;
        double height_pt, width_pt;
        unsigned int height, width;
+       double size[2];
+       double offset[2];
 
        bindtextdomain (GETTEXT_PACKAGE, PACKAGE_LOCALE_DIR);
        bind_textdomain_codeset (GETTEXT_PACKAGE, "UTF-8");
@@ -153,6 +162,31 @@ main(int argc, char **argv)
                return EXIT_FAILURE;
        }
 
+       if (option_offset != NULL) {
+               unsigned n_values;
+
+               n_values = lsm_str_parse_double_list (&option_offset, 2, offset);
+               if (n_values != 2) {
+                       fprintf (stderr, "%s\n", _("Invalid number of arguments for offset option"));
+                       return EXIT_FAILURE;
+               }
+       }
+
+       if (option_size != NULL) {
+               unsigned n_values;
+
+               n_values = lsm_str_parse_double_list (&option_size, 2, size);
+               if (n_values != 2) {
+                       fprintf (stderr, "%s\n", _("Invalid number of arguments for size option"));
+                       return EXIT_FAILURE;
+               }
+               if (size[0] <= 0.0 ||
+                   size[1] <= 0.0) {
+                       fprintf (stderr, "%s\n", _("Invalid export size"));
+                       return EXIT_FAILURE;
+               }
+       }
+
        lsm_debug_enable (option_debug_domains);
 
        if (option_input_filenames == NULL || g_strv_length (option_input_filenames) > 1) {
@@ -254,11 +288,25 @@ main(int argc, char **argv)
 
                lsm_dom_view_get_size (view, &width_pt, &height_pt, NULL);
                lsm_dom_view_get_size_pixels (view, &width, &height, NULL);
+               
+               if (option_offset == NULL) {
+                       offset_x_pt = offset_y_pt = 0.0;
+               } else {
+                       offset_x_pt = option_zoom * offset[0];
+                       offset_y_pt = option_zoom * offset[1];
+               }
 
-               width_pt *= option_zoom;
-               height_pt *= option_zoom;
-               width *= option_zoom;
-               height *= option_zoom;
+               if (option_size == NULL) {
+                       width_pt *= option_zoom;
+                       height_pt *= option_zoom;
+                       width *= option_zoom;
+                       height *= option_zoom;
+               }  else {
+                       width_pt = option_zoom * size[0];
+                       height_pt = option_zoom * size[1];
+                       width = width_pt;
+                       height = height_pt;
+               }
 
                switch (format) {
                        case FORMAT_PDF:
@@ -285,7 +333,7 @@ main(int argc, char **argv)
                cairo_surface_destroy (surface);
                cairo_scale (cairo, option_zoom, option_zoom);
 
-               lsm_dom_view_render (view, cairo, 0, 0);
+               lsm_dom_view_render (view, cairo, -offset_x_pt, -offset_y_pt);
 
                switch (format) {
                        case FORMAT_PNG: