Implemented recoloring

config.c

@@ -14,6 +14,7 @@ config_load_default(zathura_t* zathura)
   }
 
   int int_value              = 0;
+  char* string_value         = NULL;
   girara_session_t* gsession = zathura->ui.session;
 
   /* general settings */
@@ -27,6 +28,10 @@ config_load_default(zathura_t* zathura)
   int_value = 2;
   girara_setting_add(gsession, "pages-per-row", &int_value, INT, false, "Number of pages per row", NULL);
 
+  string_value = "#FFFFFF";
+  girara_setting_add(gsession, "recolor-dark-color",  string_value, STRING, false, "Recoloring (dark color)",  NULL);
+  string_value = "#000000";
+  girara_setting_add(gsession, "recolor-light-color", string_value, STRING, false, "Recoloring (light color)", NULL);
 
   /* define default shortcuts */
   girara_shortcut_add(gsession, GDK_CONTROL_MASK, GDK_c,          NULL, sc_abort,             0,                   0,               NULL);

render.c

@@ -168,6 +168,39 @@ render(zathura_t* zathura, zathura_page_t* page)
     }
   }
 
+  /* recolor */
+  if (zathura->global.recolor) {
+    /* recolor code based on qimageblitz library flatten() function
+    (http://sourceforge.net/projects/qimageblitz/) */
+
+    int r1 = zathura->ui.colors.recolor_dark_color.red    / 257;
+    int g1 = zathura->ui.colors.recolor_dark_color.green  / 257;
+    int b1 = zathura->ui.colors.recolor_dark_color.blue   / 257;
+    int r2 = zathura->ui.colors.recolor_light_color.red   / 257;
+    int g2 = zathura->ui.colors.recolor_light_color.green / 257;
+    int b2 = zathura->ui.colors.recolor_light_color.blue  / 257;
+
+    int min  = 0x00;
+    int max  = 0xFF;
+    int mean = 0x00;
+
+    float sr = ((float) r2 - r1) / (max - min);
+    float sg = ((float) g2 - g1) / (max - min);
+    float sb = ((float) b2 - b1) / (max - min);
+
+    for (unsigned int y = 0; y < page_height; y++) {
+      unsigned char* data = image + y * rowstride;
+
+      for (unsigned int x = 0; x < page_width; x++) {
+        mean = (data[0] + data[1] + data[2]) / 3;
+        data[2] = sr * (mean - min) + r1 + 0.5;
+        data[1] = sg * (mean - min) + g1 + 0.5;
+        data[0] = sb * (mean - min) + b1 + 0.5;
+        data += 4;
+      }
+    }
+  }
+
   /* draw to gtk widget */
   page->surface = surface;
   gtk_widget_set_size_request(page->drawing_area, page_width, page_height);

shortcuts.c

@@ -119,6 +119,11 @@ bool
 sc_recolor(girara_session_t* session, girara_argument_t* argument, unsigned int t)
 {
   g_return_val_if_fail(session != NULL, false);
+  g_return_val_if_fail(session->global.data != NULL, false);
+  zathura_t* zathura = session->global.data;
+
+  zathura->global.recolor = !zathura->global.recolor;
+  render_all(zathura);
 
   return false;
 }

zathura.c

@@ -104,10 +104,13 @@ zathura_init(int argc, char* argv[])
   zathura->ui.page_view             = NULL;
   zathura->ui.index                 = NULL;
 
-  /* Print settings */
+  /* print settings */
   zathura->print.settings   = NULL;
   zathura->print.page_setup = NULL;
 
+  /* global settings */
+  zathura->global.recolor = false;
+
   /* load plugins */
   zathura_document_plugins_load(zathura);
 
@@ -173,6 +176,19 @@ zathura_init(int argc, char* argv[])
   gtk_table_set_row_spacings(GTK_TABLE(zathura->ui.page_view), zathura->global.page_padding);
   gtk_table_set_col_spacings(GTK_TABLE(zathura->ui.page_view), zathura->global.page_padding);
 
+  /* parse colors */
+  char* string_value = girara_setting_get(zathura->ui.session, "recolor-dark-color");
+  if (string_value != NULL) {
+    gdk_color_parse(string_value, &(zathura->ui.colors.recolor_dark_color));
+    free(string_value);
+  }
+
+  string_value = girara_setting_get(zathura->ui.session, "recolor-light-color");
+  if (string_value != NULL) {
+    gdk_color_parse(string_value, &(zathura->ui.colors.recolor_light_color));
+    free(string_value);
+  }
+
   /* open document if passed */
   if (argc > 1) {
     zathura_document_info_t* document_info = malloc(sizeof(zathura_document_info_t));

zathura.h

@@ -44,6 +44,12 @@ typedef struct zathura_s
       girara_statusbar_item_t* page_number; /**> page number statusbar entry */
     } statusbar;
 
+    struct
+    {
+      GdkColor recolor_dark_color; /**> Dark color for recoloring */
+      GdkColor recolor_light_color; /**> Light color for recoloring */
+    } colors;
+
     GtkWidget *page_view; /**> Widget that contains all rendered pages */
     GtkWidget *index; /**> Widget to show the index of the document */
   } ui;
@@ -55,25 +61,26 @@ typedef struct zathura_s
 
   struct
   {
-    girara_list_t* plugins;
-    girara_list_t* path;
+    girara_list_t* plugins; /**> List of plugins */
+    girara_list_t* path; /**> List of plugin paths */
   } plugins;
 
   struct
   {
-    gchar* config_dir;
-    gchar* data_dir;
+    gchar* config_dir; /**> Path to the configuration directory */
+    gchar* data_dir; /**> Path to the data directory */
   } config;
 
   struct
   {
-    GtkPrintSettings* settings;
-    GtkPageSetup* page_setup;
+    GtkPrintSettings* settings; /**> Print settings */
+    GtkPageSetup* page_setup; /**> Saved page setup */
   } print;
 
   struct
   {
-    unsigned int page_padding;
+    unsigned int page_padding; /**> Padding between the pages */
+    bool recolor; /**> Recoloring mode switch */
   } global;
 
   zathura_document_t* document; /**> The current document */