Toolbox

Changes for Window_GadgetMouseScroll

Window_GadgetMouseScroll (0x82892) is generated by a limited set of gadgets on request in their gadget flags word. The flag to enable the report is labelled *_GenerateMouseScroll. Whilst it uses the phrase MouseScroll, the event is generated by any alternate pointer device operation whilst over that gadget and may in addition be generated by other, equivalent operations.

The event is generated to inform applications that the user has scrolled over one of the gadgets.

Writable gadget

The Writable Field gadget supports Writable_GenerateMouseScroll (flag 0x20) to generate the scroll notification. The gadget will also generate the new event when Page up/Page down are used.

Display field gadget

The Display Field gadget supports DisplayField_GenerateMouseScroll (flag 0x8) to generate the scroll notification.

NumberRange gadget

The NumberRange gadget does not generate the Window_GadgetMouseScroll event, but sets the flags on the Display and Writable field gadgets and consumes the event generated. The gadget is modified by the step specified for the gadget adjusters.

In addition the slider is now marked as being draggable (or scrollable) when it has adjusters or a writable field. In the past the slider was only draggable (or scrollable) when it had a writable field. A true display only number-range slider is now only possible when both the Writable and Adjusters flags are clear.

PopUp Menu gadget

The PopUp menu gadget supports PopUp_GenerateMouseScroll (flag 0x2) to generate scroll notifications. It does not manipulate the menu (or other object associated with the gadget) it triggers.

StringSet gadget

The NumberRange gadget does not generate the Window_GadgetMouseScroll event but sets the flags on the PopUp, Display and Writable field gadgets and consumes the event generated. The value displayed (if any) is modified by the scroll.

Option Button gadget

The Option Button gadget supports OptionButton_GenerateMouseScroll (flag 0x8) to generate the scroll notification.

Radio Button gadget

The Radio Button gadget supports RadioButton_GenerateMouseScroll (flag 0x8) to generate the scroll notification.

Draggable gadget

The Draggable gadget supports Draggable_GenerateMouseScroll (flag 0x200) to generate the scroll notification. Note that this form of notification is not presently supported on gadgets which use a private sprite area.

Adjuster gadget

The Adjuster gadget supports Adjuster_GenerateMouseScroll (flag 0x4) to generate the scroll notification.

This documentation is copyright 3QD Developments Ltd 2013 and may not be reproduced or published in any form without the copyright holders permission. RISC OS is subject to continuous development and improvement as such all information is reproduced by 3QD Developments Ltd in good faith and is believed to be correct at the time of publication E&OE. 3QD Developments Ltd cannot accept any liability for any loss or damage arising from the use of any information provided as part of the RISC OS Documentation.

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