Add image preview to file choosers

Co-authored-by: Thibaut Girka <thib@sitedethib.com>

main/CMakeLists.txt

@@ -127,6 +127,7 @@ SOURCES
     src/ui/util/accounts_combo_box.vala
     src/ui/util/helper.vala
     src/ui/util/label_hybrid.vala
+    src/ui/util/preview_file_chooser_native.vala
 CUSTOM_VAPIS
     ${CMAKE_BINARY_DIR}/exports/xmpp-vala.vapi
     ${CMAKE_BINARY_DIR}/exports/qlite.vapi

main/src/ui/conversation_titlebar/file_entry.vala

@@ -24,6 +24,9 @@ public class FileEntry : Plugins.ConversationTitlebarEntry, Object {
 
 public class FileWidget : Button, Plugins.ConversationTitlebarWidget {
 
+    private const int PREVIEW_SIZE = 180;
+    private const int PREVIEW_PADDING = 3;
+
     private Conversation? conversation;
     private StreamInteractor stream_interactor;
 
@@ -35,9 +38,8 @@ public class FileWidget : Button, Plugins.ConversationTitlebarWidget {
     }
 
     public void on_clicked() {
-        FileChooserNative chooser = new FileChooserNative (
-                "Select file", get_toplevel() as Window, FileChooserAction.OPEN,
-                "Select", "Cancel");
+        PreviewFileChooserNative chooser = new PreviewFileChooserNative("Select file", get_toplevel() as Window, FileChooserAction.OPEN, "Select", "Cancel");
+
 //        long max_file_size = stream_interactor.get_module(Manager.IDENTITY).get_max_file_size(conversation.account);
 //        if (max_file_size != -1) {
 //            FileFilter filter = new FileFilter();

main/src/ui/manage_accounts/dialog.vala

@@ -150,9 +150,7 @@ public class Dialog : Gtk.Dialog {
     }
 
     private void show_select_avatar() {
-        FileChooserNative chooser = new FileChooserNative (
-                _("Select avatar"), this, FileChooserAction.OPEN,
-                _("Select"), _("Cancel"));
+        PreviewFileChooserNative chooser = new PreviewFileChooserNative(_("Select avatar"), this, FileChooserAction.OPEN, _("Select"), _("Cancel"));
         FileFilter filter = new FileFilter();
         filter.add_pattern("*.png");
         filter.add_pattern("*.jpg");
@@ -162,10 +160,12 @@ public class Dialog : Gtk.Dialog {
         filter.add_pattern("*.bmp");
         filter.set_filter_name(_("Images"));
         chooser.add_filter(filter);
+
         filter = new FileFilter();
         filter.set_filter_name(_("All files"));
         filter.add_pattern("*");
         chooser.add_filter(filter);
+
         if (chooser.run() == Gtk.ResponseType.ACCEPT) {
             string uri = chooser.get_filename();
             stream_interactor.get_module(AvatarManager.IDENTITY).publish(selected_account, uri);

main/src/ui/util/preview_file_chooser_native.vala

@@ -0,0 +1,82 @@
+using Gdk;
+using Gtk;
+
+using Dino.Entities;
+
+namespace Dino.Ui {
+
+public class PreviewFileChooserNative : Object {
+    private const int PREVIEW_SIZE = 180;
+    private const int PREVIEW_PADDING = 5;
+
+    private Gtk.FileChooserNative? chooser = null;
+    private Image preview_image = new Image();
+
+    public PreviewFileChooserNative(string? title, Gtk.Window? parent, FileChooserAction action, string? accept_label, string? cancel_label) {
+        chooser = new FileChooserNative(title, parent, action, accept_label, cancel_label);
+
+        chooser.set_preview_widget(this.preview_image);
+        chooser.use_preview_label = false;
+        chooser.preview_widget_active = false;
+
+        chooser.update_preview.connect(on_update_preview);
+    }
+
+    public void add_filter(owned Gtk.FileFilter filter) {
+        chooser.add_filter(filter);
+    }
+
+    public SList<File> get_files() {
+        return chooser.get_files();
+    }
+
+    public int run() {
+        return chooser.run();
+    }
+
+    public string? get_filename() {
+        return chooser.get_filename();
+    }
+
+    private void on_update_preview() {
+        Pixbuf preview_pixbuf = get_preview_pixbuf();
+        if (preview_pixbuf != null) {
+            int extra_space = PREVIEW_SIZE - preview_pixbuf.width;
+            int smaller_half = extra_space/2;
+            int larger_half = extra_space - smaller_half;
+
+            preview_image.set_margin_start(PREVIEW_PADDING + smaller_half);
+            preview_image.set_margin_end(PREVIEW_PADDING + larger_half);
+
+            preview_image.set_from_pixbuf(preview_pixbuf);
+            chooser.preview_widget_active = true;
+        } else {
+            chooser.preview_widget_active = false;
+        }
+    }
+
+    private Pixbuf? get_preview_pixbuf() {
+        string? filename = chooser.get_preview_filename();
+        if (filename == null) {
+            return null;
+        }
+
+        int width = 0;
+        int height = 0;
+        Gdk.PixbufFormat? format = Gdk.Pixbuf.get_file_info(filename, out width, out height);
+        if (format == null) {
+            return null;
+        }
+
+        try {
+            Gdk.Pixbuf pixbuf = new Gdk.Pixbuf.from_file_at_scale(filename, PREVIEW_SIZE, PREVIEW_SIZE, true);
+            pixbuf = pixbuf.apply_embedded_orientation();
+            return pixbuf;
+        } catch (Error e) {
+            return null;
+        }
+    }
+
+}
+
+}