blob: c54e7c9d107c9899d5aad5ed181f2998dce4f5df (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
|
These are some notes I thought will come in handly as I work through the
code and write new code.
Event handling
===============
* Each platform gets the events from the underlying graphics library.
* Events get caught and translated into a fpGUI message record.
* The fpGUI message record gets placed (using fpgPostMessage) in a custom
fpGUI message queue (which is a linkedlist structure with 512 links).
* From there the fpGUI message records get delivered to the specific window.
* Certain messages traverse up the hierarchy to be processed by all parents.
* Messages get delivered up the hierarchy using the TObject.Dispatch method
* Messages get delivered down the hierarchy using the TComponent.Components
property.
* The standard 'message' language feature of Object Pascal gets used to in
the class interfaces section to capture a posted message (event). All
standard FPGM_xxx messages get handled in the TfpgWidget and TfpgForm
classes.
Pen and Brush support (X11)
===========================
* They come from the GC
* They are seperate GC's and swapped around when needed in the different
Xlib drawing routines. Both created with the XCreateGC() function
eg:
d->gc = Pen
d->gc_brush = Brush
XFillRectangle(dpy, screen, d->gc_brush, .....);
XDrawRectangle(dpy, screen, d->gc, .....);
* Updating the Pen and Brush attributes are done with a call to XChangeGC(),
passing in the relevant GC (d->gc or d->gc_brush).
|
