83Plus:Hooks:9B94 - Revision history

Mmartin: /* Using the Hook */

2006-07-10T19:23:50Z

‎Using the Hook

FloppusMaximus: /* Synopsis */

2005-04-02T05:24:08Z

‎Synopsis

FloppusMaximus at 03:26, 2 April 2005

2005-04-02T03:26:27Z

JasonM at 02:10, 2 April 2005

2005-04-02T02:10:16Z

New page

[[Category:83Plus:Hooks:By Address|9B94 - Graph Hook]]
[[Category:83Plus:Hooks:By Name|Graph Hook]]
== Synopsis ==
'''Name:''' Graph Hook

'''Hook Pointer Block Address:''' [[83Plus:RAM:9B94|9B94]]

'''Hook Enable BCALL:''' [[83Plus:BCALLs:4FB7|4FB7]]

'''Hook Disable BCALL:''' [[83Plus:BCALLs:4FBA|4FBA]]

'''Hook Call BCALL:''' ''Unknown''

'''Hook Active Flag:''' 3, (iy + 35h)

This hook allows you to recieve notifications about events related to the graph context, allowing you to change some events.

== Using the Hook ==
Like most hooks, the value in A determines what you are being notified of.

* '''A = 00h:''' We are switching to the graph context. Return flags are ignored.
* '''A = 02h:''' The OS is about to draw the X/Y coordinates of both the free-moving cursor and also the trace cursor. Returning with zero reset will prevent drawing of the X/Y coordinates. '''Side Note:''' You can draw the coordinates with the undocumented B_CALL [[83Plus:BCALLs:489D|PutXY]].
* '''A = 04h:''' The OS is about to accept user input again (it is done doing whatever processing it was doing.) Here you could draw any extra UI elements you want to appear atop the graph. Return flags seem to be ignored.
* '''A = 05h:''' The OS is about to blink the free-moving cursor (not the trace cursor, if you want to change that, use the trace hook.) Returning with zero reset will cancel the blink (it'll stay at whatever state it's currently in.)
* '''A = 06h:''' A key was pressed, passed in B. You can cancel the keypress if you return with the zero flag reset, otherwise return the keypress you want to occur in B.
* '''A = 07h:''' The OS is about to draw the graph. This could just include presenting what's in plotSScreen, or actually doing the graphing procedure. Returning with zero reset will cause the OS not to draw the graph / present the graph buffer: you can then draw whatever you want. If you want to control what is actually drawn during a graphing procedure, check out the [[83Plus:Hooks:9BA0|regraph hook]].

== Comments ==
Note: When you press graph to start the context, the OS fires this event after event 00h, with B being kGraph. I'm not sure why they do this, but if you cancel the keypress event 07h won't be fired.

@@ Line 19: / Line 19: @@
 * '''A = 00h:''' We are switching to the graph context. Return flags are ignored.
-* '''A = 02h:''' The OS is about to draw the X/Y coordinates of both the free-moving cursor and also the trace cursor. Returning with zero reset will prevent drawing of the X/Y coordinates. '''Side Note:''' You can draw the coordinates with the undocumented B_CALL [[83Plus:BCALLs:489D|PutXY]].
+* '''A = 02h:''' The OS is about to draw the X/Y coordinates of both the free-moving cursor and also the trace cursor. Returning with zero reset will prevent drawing of the X/Y coordinates and the movement of the cursor. '''Side Note:''' You can draw the coordinates with the undocumented B_CALL [[83Plus:BCALLs:489D|PutXY]].
 * '''A = 04h:''' The OS is about to accept user input again (it is done doing whatever processing it was doing.) Here you could draw any extra UI elements you want to appear atop the graph. Return flags seem to be ignored.
 * '''A = 05h:''' The OS is about to blink the free-moving cursor (not the trace cursor, if you want to change that, use the trace hook.) Returning with zero reset will cancel the blink (it'll stay at whatever state it's currently in.)

@@ Line 11: / Line 11: @@
 '''Hook Call BCALL:''' ''Unknown''
-'''Hook Active Flag:''' 3, (iy + 35h)
+'''Hook Active Flag:''' [[83Plus:Flags:35#Bit_3|3, (iy + 35h)]]
 This hook allows you to recieve notifications about events related to the graph context, allowing you to change some events.

@@ Line 1: / Line 1: @@
-[[Category:83Plus:Hooks:By Address|9B94 - Graph Hook]]
+[[Category:83Plus:Hooks:By Address|9B94 - Graph Hook]] [[Category:83Plus:Hooks:By Name|Graph Hook]]
 [[Category:83Plus:Hooks:By Name|Graph Hook]]
 == Synopsis ==
 '''Name:''' Graph Hook