Remove the additional SORT_WIDTH spacing logic in Tree column rendering.

[ShahzaibIbrahim]

Since Windows 7, the sort indicator in tree columns is rendered above the column header text, whereas in Windows XP it was placed next to the text. The original SWT implementation added extra pixels (SORT_WIDTH) to the column width to make space for the indicator.

In Windows XP, the indicator was next to the line, where the logic probably originated from. See,

From Windows 7 onwards, the sort indicator is on top like this,

[github-actions]

Test Results

   546 files  ±0     546 suites  ±0   32m 9s ⏱️ -8s
 4 431 tests ±0   4 414 ✅ ±0   17 💤 ±0  0 ❌ ±0 
16 764 runs  ±0  16 637 ✅ ±0  127 💤 ±0  0 ❌ ±0 

Results for commit c3b03fe. ± Comparison against base commit f858239.

♻️ This comment has been updated with latest results.

[BeckerWdf]

I did a code review and the changes look good to me.
As I am on macOS I cannot test the changes

[arunjose696]

@ShahzaibIbrahim is there some snippet to test this change?

[arunjose696]

I have tested the changes with the below snippet, the changes look good, without this change the column header is cropped of as in the left image and with this the full header is visible. So changes LGTM.

TreeColumnImageHeaderExample (Code)

package org.eclipse.swt.snippets;

import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

public class TreeColumnImageHeaderExample {

    public static void main(String[] args) {
        final Display display = new Display();
        System.setProperty("swt.autoScale", "quarter");
        System.setProperty("swt.autoScale.updateOnRuntime", "true");
        Shell shell = new Shell(display);
        shell.setText("Tree with Images in Header");
        shell.setLayout(new FillLayout());

        final Tree tree = new Tree(shell, SWT.MULTI | SWT.FULL_SELECTION);
        tree.setHeaderVisible(true);
        tree.setLinesVisible(true);

        int columnCount = 4;
        Image[] headerImages = new Image[columnCount];

        // Load sample images (replace with your own image paths)
        for (int i = 0; i < columnCount; i++) {
            headerImages[i] = new Image(display, 16, 16); // Placeholder blank image
            GC gc = new GC(headerImages[i]);
            gc.setBackground(display.getSystemColor(SWT.COLOR_BLUE));
            gc.fillRectangle(0, 0, 16, 16); // Simple colored square as image
            gc.dispose();
        }

        // Create columns with text and images
        for (int i = 0; i < columnCount; i++) {
            TreeColumn column = new TreeColumn(tree, SWT.NONE);
            column.setText("Column " + i);
            column.setImage(headerImages[i]);
        }

        // Populate tree items
        int itemCount = 3;
        for (int i = 0; i < itemCount; i++) {
            TreeItem item1 = new TreeItem(tree, SWT.NONE);
            item1.setText("item " + i);
            for (int c = 1; c < columnCount; c++) {
                item1.setText(c, "item [" + i + "-" + c + "]");
            }
            for (int j = 0; j < itemCount; j++) {
                TreeItem item2 = new TreeItem(item1, SWT.NONE);
                item2.setText("item [" + i + " " + j + "]");
                for (int c = 1; c < columnCount; c++) {
                    item2.setText(c, "item [" + i + " " + j + "-" + c + "]");
                }
                for (int k = 0; k < itemCount; k++) {
                    TreeItem item3 = new TreeItem(item2, SWT.NONE);
                    item3.setText("item [" + i + " " + j + " " + k + "]");
                    for (int c = 1; c < columnCount; c++) {
                        item3.setText(c, "item [" + i + " " + j + " " + k + "-" + c + "]");
                    }
                }
            }
        }

        // Optional: Custom selection gradient (kept from your original snippet)
        tree.addListener(SWT.EraseItem, event -> {
            event.detail &= ~SWT.HOT;
            if ((event.detail & SWT.SELECTED) != 0) {
                GC gc = event.gc;
                Rectangle rect = event.getBounds();
                Color foreground = gc.getForeground();
                Color background = gc.getBackground();
                gc.setForeground(display.getSystemColor(SWT.COLOR_RED));
                gc.setBackground(display.getSystemColor(SWT.COLOR_LIST_BACKGROUND));
                gc.fillGradientRectangle(0, rect.y, 500, rect.height, false);
                gc.setForeground(foreground);
                gc.setBackground(background);
                event.detail &= ~SWT.SELECTED;
            }
        });

        tree.setSortColumn(tree.getColumn(2));
        tree.setSortColumn(tree.getColumn(1));
        tree.setSortDirection(SWT.UP);
        for (int i = 0; i < columnCount; i++) {
            tree.getColumn(i).pack();
        }
        tree.setSelection(tree.getItem(0));

        shell.setSize(500, 200);
        shell.open();

        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }

        // Dispose images to avoid memory leaks
        for (Image img : headerImages) {
            img.dispose();
        }

        display.dispose();
    }
}

---

[arunjose696]

@ShahzaibIbrahim can you fix the conflict with master