[NETBEANS-2614] Improve icon scaling on HiDPI displays, and prepare ImageUtilities for HiDPI icons.

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 11.0
• Fix Version/s: 11.1
• Component/s: platform - Other
• Labels: HiDPI pull-request-available

Environment

Windows, Linux, and MacOS.

• Assignee: Eirik Bakke
• Reporter: Eirik Bakke
• Created: 29/May/19 18:56
• Updated: 03/Nov/20 15:46
• Resolved: 15/Jun/19 15:04

Description

To look good on HiDPI/Retina displays, the NetBeans IDE, and NetBeans Platform (RCP) applications, will eventually need to provide high-resolution versions of various image asset (typically icons). In the shorter term, there are also a few tricks that can be applied to make the existing low-resolution icons render better on HiDPI monitors, such as setting RenderingHints.VALUE_INTERPOLATION_BICUBIC before painting each icon. See the attached before/after screenshots to see the difference (be sure to view the screenshots at 100% scaling).

Throughout the NetBeans codebase, two different APIs are used interchangeably to represent icon: javax.swing.Icon and java.awt.Image. The NetBeans ImageUtilities class provides methods for loading either, and for converting instances of one to instances the other.

Having now implementing scalable window system icons (NETBEANS-1238, NETBEANS-1260), prototype SVG icon loading (NETBEANS-2604), and a HiDPI-enabled splash screen ( https://github.com/apache/netbeans/pull/1246 ), the following design seems the most feasible:

1. Scalable icon implementations (such as VectorIcon or a future SVGIcon) should be implemented as custom implementations of the javax.swing.Icon interface.
2. The various methods in ImageUtilities should be updated to preserve custom Icon instances even as an Icon is converted to an Image and back (i.e. make image2Icon(icon2image(icon)) reversible).
3. Other parts of the codebase should be updated as necessary to use ImageUtilities.image2Icon(image) instead of "new ImageIcon(image)", and to use "Icon.paintIcon" instead of "Graphics.drawImage". (Most of the IDE code already does the right thing.)

This issue tracks the required changes to ImageUtilities, as well as the previously mentioned icon rendering improvements, which will serve as a visual demonstration that the right painting code is being invoked.

Issue Links

• blocks: NETBEANS-2604 Support SVG icon loading from ImageUtilities
• incorporates: NETBEANS-1586 Make ImageUtilities.createDisabledIcon work with HiDPI icons
• links to: GitHub Pull Request #1273
• mentioned in: Page Loading...