Huge icons in Open Resources dialog

[trancexpress]

To reproduce:

1. Start Eclipse in a new workspace.
2. Create a project.
3. Create a text.txt file in the root of the new project.
4. Create a text.moc file.
5. Ctrl+Shift+R to open the "Open Resources" dialog.
6. Type "test".
7. Observe huge icons.

See screen recording:

open_resource_dialog_huge_icons.mp4

I can reproduce this on Linux, GTK3, with:

Eclipse SDK
Version: 2026-03 (4.39)
Build id: I20260113-1800

Seems like the icons of external editors are not scaled properly.

SWT snippet:

package test;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.program.Program;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class TestProgram {
	public static void main(String[] args) {
		Display display = new Display();
		Program program = Program.findProgram("moc");
		ImageData imageData = program.getImageData();
		Image image = new Image(display, imageData);
		Shell shell = new Shell(display);
		shell.setSize(100, 100);
		shell.setLayout(new FillLayout());
		shell.setText("Snippet 36");
		Canvas c = new Canvas(shell, SWT.BORDER);
		c.addPaintListener(new PaintListener() {
			@Override
			public void paintControl(PaintEvent e) {
				e.gc.drawImage(image, 0, 0);
			}
		});
		shell.open();
		while (!shell.isDisposed()) {
			if (!display.readAndDispatch())
				display.sleep();
		}
		display.dispose();
	}
}

And GTK3 snippet showing the height/width:

#include <gtk/gtk.h>

// gcc -g icon.c  `pkg-config --cflags --libs gtk+-3.0`  -o IconExample && ./IconExample


int
main (int argc, char **argv)
{
	GtkWidget *window, *scrolled_window;
	GtkListStore *liststore;
	GtkTreeIter iter;

	gtk_init(&argc, &argv);

	window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
	g_signal_connect(window, "delete_event", gtk_main_quit, NULL);
	gtk_window_set_default_size(GTK_WINDOW(window), 200, 100);

	scrolled_window = gtk_scrolled_window_new(NULL, NULL);

	GIcon *gicon = g_icon_new_for_string("emacs", NULL);
	GtkIconTheme *icon_theme = gtk_icon_theme_get_default();
	GtkIconInfo *gicon_info = gtk_icon_theme_lookup_by_gicon(icon_theme, gicon, 16/*size*/, 0);
	GdkPixbuf *pixbuf = gtk_icon_info_load_icon(gicon_info, NULL);

	int height = gdk_pixbuf_get_height(pixbuf);
	int width = gdk_pixbuf_get_width(pixbuf);
	g_print("height=%d, width=%d\n", height, width);

	gtk_container_add (GTK_CONTAINER (window), scrolled_window);

	gtk_widget_show_all(window);

	gtk_main();

	return 0;
}

$  gcc -g icon.c  `pkg-config --cflags --libs gtk+-3.0`  -o IconExample && ./IconExample
height=48, width=48

Varying the size parameter seems to make no difference. Though there are different icons available:

$ find /usr/share/icons/ -name "emacs.png"
/usr/share/icons/hicolor/16x16/apps/emacs.png
/usr/share/icons/hicolor/24x24/apps/emacs.png
/usr/share/icons/hicolor/32x32/apps/emacs.png
/usr/share/icons/hicolor/48x48/apps/emacs.png
/usr/share/icons/hicolor/128x128/apps/emacs.png

[trancexpress]

I can reproduce with:

Eclipse SDK
Version: 2024-03 (4.31)
Build id: I20240229-0520

I cannot reproduce with:

Eclipse SDK
Version: 2023-12 (4.30)
Build id: I20231201-0110

Note that there are no external editor icons with 4.30, the icon I see is a generic text file icon.

Nothing that I see in N&N for 4.31: https://eclipse.dev/eclipse/news/4.31/platform.html

[trancexpress]

Looking at org.eclipse.swt.program.Program.getImageData(int), with input program kate:

public ImageData getImageData(int zoom) {
	if (iconPath == null) return null;
	ImageData data = null;

	long gicon = OS.g_icon_new_for_string(Converter.javaStringToCString(iconPath), null);
	if (gicon != 0) {
		long pixbuf = 0;
		if (GTK.GTK4) {
			...
		} else {
			long icon_theme = GTK3.gtk_icon_theme_get_default();
			long gicon_info = GTK3.gtk_icon_theme_lookup_by_gicon(icon_theme, gicon, 16/*size*/, 0);
			if (gicon_info != 0) {
				pixbuf = GTK3.gtk_icon_info_load_icon(gicon_info, null);
				OS.g_object_unref(gicon_info);
			}
		}

		// Unref gicon as we have retrieved the required pixbuf
		OS.g_object_unref(gicon);

		if (pixbuf != 0) {
			int stride = GDK.gdk_pixbuf_get_rowstride(pixbuf);
			long pixels = GDK.gdk_pixbuf_get_pixels(pixbuf);
			int height = GDK.gdk_pixbuf_get_height(pixbuf);
			int width = GDK.gdk_pixbuf_get_width(pixbuf);
			boolean hasAlpha = GDK.gdk_pixbuf_get_has_alpha(pixbuf);

			// Move pixbuf memory to srcData and unref pixbuf
			byte[] srcData = new byte[stride * height];
			C.memmove(srcData, pixels, srcData.length);
			OS.g_object_unref(pixbuf);

			if (hasAlpha) {
				PaletteData palette = new PaletteData(0xFF000000, 0xFF0000, 0xFF00);
				data = new ImageData(width, height, 32, palette, 4, srcData);
				data.bytesPerLine = stride;
				int s = 3, a = 0;
				byte[] alphaData = new byte[width * height];
				for (int y = 0; y < height; y++) {
					for (int x = 0; x < width; x++) {
						alphaData[a++] = srcData[s];
						srcData[s] = 0;
						s+=4;
					}
				}
				data.alphaData = alphaData;
			} else {
				PaletteData palette = new PaletteData(0xFF0000, 0xFF00, 0xFF);
				data = new ImageData(width, height, 24, palette, 4, srcData);
				data.bytesPerLine = stride;
			}
		}
	}

	return data;
}

We want size "16", whatever that means:

long gicon_info = GTK3.gtk_icon_theme_lookup_by_gicon(icon_theme, gicon, 16/*size*/, 0);

But height and width are 48 when I debug:

		if (pixbuf != 0) {
			int stride = GDK.gdk_pixbuf_get_rowstride(pixbuf);
			long pixels = GDK.gdk_pixbuf_get_pixels(pixbuf);
			int height = GDK.gdk_pixbuf_get_height(pixbuf);
			int width = GDK.gdk_pixbuf_get_width(pixbuf);

gtk_icon_theme_lookup_by_gicon ()

GtkIconInfo *
gtk_icon_theme_lookup_by_gicon (GtkIconTheme *icon_theme,
                                GIcon *icon,
                                gint size,
                                GtkIconLookupFlags flags);

Looks up an icon and returns a GtkIconInfo containing information such as the filename of the icon. The icon can then be rendered into a pixbuf using gtk_icon_info_load_icon().

When rendering on displays with high pixel densities you should not use a size multiplied by the scaling factor returned by functions like gdk_window_get_scale_factor(). Instead, you should use gtk_icon_theme_lookup_by_gicon_for_scale(), as the assets loaded for a given scaling factor may be different.
Parameters

icon_theme
	

a GtkIconTheme
	 

icon
	

the GIcon to look up
	 

size
	

desired icon size
	 

flags
	

flags modifying the behavior of the icon lookup
	 
Returns

a GtkIconInfo containing information about the icon, or NULL if the icon wasn’t found. Unref with g_object_unref().

[nullable][transfer full]

Since: 2.14