Allow image formats to be disabled from dillorc

Makes disabling certain formats posible without the need to rebuild
Dillo from source.

See: #312

ChangeLog

@@ -28,6 +28,7 @@ dillo-3.2.0 [Not released yet]
  - Improve image resize logic to always try to preserve the aspect ratio.
  - Reload current page on SIGUSR1 signal
  - Print library versions and enabled features with dillo -v.
+ - Allow image formats to be ignored with the "ignore_image_formats" option.
    Patches: Rodrigo Arias Mallo
 +- Add primitive support for SVG using the nanosvg.h library.
  - Add support for ch, rem, vw, vh, vmin and vmax CSS units.

dillorc

@@ -19,6 +19,12 @@
 # menu.)
 #load_images=YES
 
+# A space separated list of image formats that will be ignored (not viewed).
+# An option to download the image will be offered instead.
+# Available formats: gif, png, webp, jpeg and svg.
+# ignore_image_formats="webp svg"
+#ignore_image_formats=""
+
 # Change this if you want background images to be loaded initially.
 # (While browsing, this can be changed from the tools/settings menu.)
 #load_background_images=NO

src/dicache.c

@@ -25,13 +25,23 @@
 #include "dsvg.h"
 
 enum {
-   DIC_Gif,
+   DIC_Gif = 0,
    DIC_Png,
    DIC_Webp,
    DIC_Jpeg,
-   DIC_Svg
+   DIC_Svg,
+   DIC_MAX
 };
 
+static const char *format_name[DIC_MAX] = {
+   [DIC_Gif]  = "gif",
+   [DIC_Png]  = "png",
+   [DIC_Webp] = "webp",
+   [DIC_Jpeg] = "jpeg",
+   [DIC_Svg]  = "svg"
+};
+
+static int disabled_formats[DIC_MAX] = { 0 };
 
 /**
  * List of DICacheEntry. May hold several versions of the same image,
@@ -67,6 +77,15 @@ void a_Dicache_init(void)
 {
    CachedIMGs = dList_new(256);
    dicache_size_total = 0;
+
+   if (prefs.ignore_image_formats) {
+      for (int i = 0; i < DIC_MAX; i++) {
+         if (dStriAsciiStr(prefs.ignore_image_formats, format_name[i])) {
+            disabled_formats[i] = 1;
+            _MSG("Image format %s disabled\n", format_name[i]);
+         }
+      }
+   }
 }
 
 /**
@@ -372,6 +391,11 @@ static void *Dicache_image(int ImgType, const char *MimeType, void *Ptr,
 
    dReturn_val_if_fail(MimeType && Ptr, NULL);
 
+   if (ImgType >= 0 && ImgType < DIC_MAX && disabled_formats[ImgType]) {
+      _MSG("Ignoring image format %s\n", format_name[ImgType]);
+      return NULL;
+   }
+
    if (!web->Image) {
       web->Image =
          a_Image_new_with_dw(web->bw->render_layout, NULL, web->bgColor, 0);

src/prefs.c

@@ -76,6 +76,7 @@ void a_Prefs_init(void)
    prefs.adjust_min_width = TRUE;
    prefs.adjust_table_min_width = TRUE;
    prefs.load_images=TRUE;
+   prefs.ignore_image_formats = NULL;
    prefs.load_background_images=FALSE;
    prefs.load_stylesheets=TRUE;
    prefs.middle_click_drags_page = TRUE;

src/prefs.h

@@ -97,6 +97,7 @@ typedef struct {
    bool_t show_quit_dialog;
    bool_t fullwindow_start;
    bool_t load_images;
+   char *ignore_image_formats;
    bool_t load_background_images;
    bool_t load_stylesheets;
    bool_t parse_embedded_css;

src/prefsparser.cc

@@ -186,6 +186,7 @@ void PrefsParser::parse(FILE *fp)
       { "adjust_min_width", &prefs.adjust_min_width, PREFS_BOOL, 0 },
       { "adjust_table_min_width", &prefs.adjust_table_min_width, PREFS_BOOL, 0 },
       { "load_images", &prefs.load_images, PREFS_BOOL, 0 },
+      { "ignore_image_formats", &prefs.ignore_image_formats, PREFS_STRING, 0 },
       { "load_background_images", &prefs.load_background_images, PREFS_BOOL, 0 },
       { "load_stylesheets", &prefs.load_stylesheets, PREFS_BOOL, 0 },
       { "middle_click_drags_page", &prefs.middle_click_drags_page,