Evaluate rendering limitations when migrating from GDC-Native

Describes rendering differences and limitations when migrating applications from GDC-Native to GBC, including window management, MDI support, and customization options.

Application resizing and display differences

GBC applications can display on different display sizes and devices, but an exact pixel-by-pixel match with GDC-Native cannot be expected.

For applications rendering in the GDC-Native, you may have sized your application forms to fit in a sized area of a monitor. There is no guarantee that the application will render inside a browser tab at the exact same size. To ensure that your application works for your target devices, review your application forms.

Pop-up windows

The GBC is a web client and not a fully-implemented windows manager. Unlike GDC-Native, the GDC-UR (Universal Rendering), which uses the GBC rendering engine, consolidates all windows into a single container, while GDC-Native allows multiple independent window containers to be open at the same time.

The GBC displays a normal (non-modal) window — a plain page — in the web view. If a modal window is opened, it is displayed over the normal window. Multiple modal windows may open over the normal window, which stays displayed beneath them. Each modal window is stacked on top of the normal window, similar to the GDC and any standard windowing system.

If in your GDC-Native application, you have a window B that is opened on top of window A, and window A has useful information, consider opening window B as modal. This can be accomplished by referencing the default.4st window style and setting the attribute STYLE="dialog" in the Genero BDL code:

OPEN window msg WITH FORM "MyWindowB" ATTRIBUTES (STYLE="dialog")

Window B then displays as a pop-up window.

An alternative is to consolidate window A and window B together as one window.

If you already have pop-up windows in your GDC-Native application, and you want to have consistency between windows in GDC and GBC, set the windowType style attribute to modal in the Genero style for Window.dialog (in the default.4st).

Note:

Any presentation style (4st) element bound to a window may contain the windowType attribute.

Excerpt from $FGLDIR/lib/default.4st:

<Style name="Window.dialog">
  <StyleAttribute name="windowType" value="modal" />
  <StyleAttribute name="sizable" value="no" />
  <StyleAttribute name="position" value="center" />
  <StyleAttribute name="actionPanelPosition" value="bottom" />
  <StyleAttribute name="ringMenuPosition" value="bottom" />
  <StyleAttribute name="toolBarPosition" value="none" />
  <StyleAttribute name="statusBarType" value="none" />
  <StyleAttribute name="errorMessagePosition" value="popup" />
</Style>

Multiple Document Interface

Multiple Document Interface (MDI) is not applicable for web applications.

Customization

It is likely you will want to apply some corporate styling to your user interface. For example, you may want to use your corporate colors or add your company logo.

Before you migrate your application, try out some of the customization exercises in Customization. For example, change the favicon image or add header text.