Add new widget "image" which allows to display an image file

* The node's content is the file path.
  Absolute paths should work, the preferred way is to specify a
  relative path, though, which will be interpreted relatively to the
  .inx file's location
* The attributes "width/height" allows to override the native size
  of the image.

4 files changed, 155 insertions, 1 deletions

diff --git a/src/extension/CMakeLists.txt b/src/extension/CMakeLists.txt
index 032b9cd4c..be8ee38f1 100644
--- a/src/extension/CMakeLists.txt
+++ b/src/extension/CMakeLists.txt
@@ -63,6 +63,7 @@ set(extension_SRC
 	prefdialog/parameter-string.cpp
 	prefdialog/widget.cpp
 	prefdialog/widget-box.cpp
+	prefdialog/widget-image.cpp
 	prefdialog/widget-label.cpp
 	prefdialog/widget-separator.cpp
 	prefdialog/widget-spacer.cpp
@@ -141,6 +142,7 @@ set(extension_SRC
 	prefdialog/parameter-string.h
 	prefdialog/widget.h
 	prefdialog/widget-box.h
+	prefdialog/widget-image.h
 	prefdialog/widget-label.h
 	prefdialog/widget-separator.h
 	prefdialog/widget-spacer.h
diff --git a/src/extension/prefdialog/widget-image.cpp b/src/extension/prefdialog/widget-image.cpp
new file mode 100644
index 000000000..4f5e11dec
--- /dev/null
+++ b/src/extension/prefdialog/widget-image.cpp
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
+ * Image widget for extensions
+ *//*
+ * Authors:
+ *   Patrick Storz <eduard.braun2@gmx.de>
+ *
+ * Copyright (C) 2019 Authors
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include "widget-image.h"
+
+#include <glibmm/fileutils.h>
+#include <glibmm/miscutils.h>
+#include <gtkmm/image.h>
+
+#include "xml/node.h"
+#include "extension/extension.h"
+
+namespace Inkscape {
+namespace Extension {
+
+
+WidgetImage::WidgetImage(Inkscape::XML::Node *xml, Inkscape::Extension::Extension *ext)
+    : InxWidget(xml, ext)
+{
+    std::string image_path;
+
+    // get path to image
+    const char *content = nullptr;
+    if (xml->firstChild()) {
+        content = xml->firstChild()->content();
+    }
+    if (content) {
+        image_path = content;
+    } else {
+        g_warning("Missing path for image widget in extension '%s'.", _extension->get_id());
+        return;
+    }
+
+    // make sure path is absolute (relative paths are relative to .inx file's location)
+    if (!Glib::path_is_absolute(image_path)) {
+        image_path = Glib::build_filename(_extension->get_base_directory(), image_path);
+    }
+
+    // check if image exists
+    if (Glib::file_test(image_path, Glib::FILE_TEST_IS_REGULAR)) {
+        _image_path = image_path;
+    } else {
+        g_warning("Image file ('%s') not found for image widget in extension '%s'.",
+                  image_path.c_str(), _extension->get_id());
+    }
+
+    // parse width/height attributes
+    const char *width = xml->attribute("width");
+    const char *height = xml->attribute("height");
+    if (width && height) {
+        _width = strtoul(width, nullptr, 0);
+        _height = strtoul(height, nullptr, 0);
+    }
+}
+
+/** \brief  Create a label for the description */
+Gtk::Widget *WidgetImage::get_widget(sigc::signal<void> * /*changeSignal*/)
+{
+    if (_hidden || _image_path.empty()) {
+        return nullptr;
+    }
+
+    Gtk::Image *image = Gtk::manage(new Gtk::Image(_image_path));
+
+    // resize if requested
+    if (_width && _height) {
+        Glib::RefPtr<Gdk::Pixbuf> pixbuf = image->get_pixbuf();
+        pixbuf = pixbuf->scale_simple(_width, _height, Gdk::INTERP_BILINEAR);
+        image->set(pixbuf);
+    }
+
+    image->show();
+
+    return dynamic_cast<Gtk::Widget *>(image);
+}
+
+}  /* namespace Extension */
+}  /* namespace Inkscape */
diff --git a/src/extension/prefdialog/widget-image.h b/src/extension/prefdialog/widget-image.h
new file mode 100644
index 000000000..95dd4d5d1
--- /dev/null
+++ b/src/extension/prefdialog/widget-image.h
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
+ * Image widget for extensions
+ *//*
+ * Authors:
+ *   Patrick Storz <eduard.braun2@gmx.de>
+ *
+ * Copyright (C) 2019 Authors
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#ifndef SEEN_INK_EXTENSION_WIDGET_IMAGE_H
+#define SEEN_INK_EXTENSION_WIDGET_IMAGE_H
+
+#include "widget.h"
+
+#include <string>
+
+namespace Gtk {
+	class Widget;
+}
+
+namespace Inkscape {
+namespace Xml {
+	class Node;
+}
+
+namespace Extension {
+
+/** \brief  A label widget */
+class WidgetImage : public InxWidget {
+public:
+    WidgetImage(Inkscape::XML::Node *xml, Inkscape::Extension::Extension *ext);
+
+    Gtk::Widget *get_widget(sigc::signal<void> *changeSignal) override;
+private:
+    /** \brief  Path to image file (relative paths are relative to the .inx file location). */
+    std::string _image_path;
+
+    /** desired width of image when rendered on screen (in px) */
+    unsigned int _width = 0;
+    /** desired height of image when rendered on screen (in px) */
+    unsigned int _height = 0;
+};
+
+}  /* namespace Extension */
+}  /* namespace Inkscape */
+
+#endif /* SEEN_INK_EXTENSION_WIDGET_IMAGE_H */
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :
diff --git a/src/extension/prefdialog/widget.cpp b/src/extension/prefdialog/widget.cpp
index da4b6545d..d4f33f7af 100644
--- a/src/extension/prefdialog/widget.cpp
+++ b/src/extension/prefdialog/widget.cpp
@@ -13,6 +13,7 @@
 #include "parameter.h"
 #include "widget.h"
 #include "widget-box.h"
+#include "widget-image.h"
 #include "widget-label.h"
 #include "widget-separator.h"
 #include "widget-spacer.h"
@@ -48,6 +49,8 @@ InxWidget *InxWidget::make(Inkscape::XML::Node *in_repr, Inkscape::Extension::Ex
         g_warning("InxWidget without name in extension '%s'.", in_ext->get_id());
     } else if (!strcmp(name, "hbox") || !strcmp(name, "vbox")) {
         widget = new WidgetBox(in_repr, in_ext);
+    } else if (!strcmp(name, "image")) {
+        widget = new WidgetImage(in_repr, in_ext);
     } else if (!strcmp(name, "label")) {
         widget = new WidgetLabel(in_repr, in_ext);
     } else if (!strcmp(name, "separator")) {
@@ -67,7 +70,8 @@ InxWidget *InxWidget::make(Inkscape::XML::Node *in_repr, Inkscape::Extension::Ex
 bool InxWidget::is_valid_widget_name(const char *name)
 {
     // keep in sync with names supported in InxWidget::make() above
-    static const std::vector<std::string> valid_names = {"hbox", "vbox", "label", "separator", "spacer", "param"};
+    static const std::vector<std::string> valid_names =
+        {"hbox", "vbox", "image", "label", "separator", "spacer", "param"};
 
     if (std::find(valid_names.begin(), valid_names.end(), name) != valid_names.end()) {
         return true;