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Improve docs about subclassing

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- fix syntax errors in example code, e.g.: children_ is private
- use FLTK coding style
- improve alignment
This commit is contained in:
Albrecht Schlosser 2024-10-24 17:59:18 +02:00
parent eb545c981b
commit f9f89be7d7
1 changed files with 41 additions and 39 deletions
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80
documentation/src/subclassing.dox
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@ -47,8 +47,8 @@ pass the same arguments:
\code
MyClass::MyClass(int x, int y, int w, int h, const char *label)
: Fl_Widget(x, y, w, h, label) {
// do initialization stuff...
: Fl_Widget(x, y, w, h, label) {
// do initialization stuff...
}
\endcode
@ -57,19 +57,19 @@ Fl_Widget's protected constructor sets \p x(), \p y(),
and initializes the other instance variables to:
\code
type(0);
box(FL_NO_BOX);
color(FL_BACKGROUND_COLOR);
selection_color(FL_BACKGROUND_COLOR);
labeltype(FL_NORMAL_LABEL);
labelstyle(FL_NORMAL_STYLE);
labelsize(FL_NORMAL_SIZE);
labelcolor(FL_FOREGROUND_COLOR);
align(FL_ALIGN_CENTER);
callback(default_callback,0);
flags(ACTIVE|VISIBLE);
image(0);
deimage(0);
type(0);
box(FL_NO_BOX);
color(FL_BACKGROUND_COLOR);
selection_color(FL_BACKGROUND_COLOR);
labeltype(FL_NORMAL_LABEL);
labelstyle(FL_NORMAL_STYLE);
labelsize(FL_NORMAL_SIZE);
labelcolor(FL_FOREGROUND_COLOR);
align(FL_ALIGN_CENTER);
callback(default_callback,0);
flags(ACTIVE|VISIBLE);
image(0);
deimage(0);
\endcode
\section subclassing_protected Protected Methods of Fl_Widget
@ -118,22 +118,22 @@ see what parts of your widget need redrawing.</I> The \p handle()
method can then set individual damage bits to limit the amount of drawing
that needs to be done:
\code
MyClass::handle(int event) {
...
if (change_to_part1) damage(1);
if (change_to_part2) damage(2);
if (change_to_part3) damage(4);
}
MyClass::draw() {
if (damage() & FL_DAMAGE_ALL) {
... draw frame/box and other static stuff ...
int MyClass::handle(int event) {
// ...
if (change_to_part1) damage(1);
if (change_to_part2) damage(2);
if (change_to_part3) damage(4);
}
if (damage() & (FL_DAMAGE_ALL | 1)) draw_part1();
if (damage() & (FL_DAMAGE_ALL | 2)) draw_part2();
if (damage() & (FL_DAMAGE_ALL | 4)) draw_part3();
}
void MyClass::draw() {
if (damage() & FL_DAMAGE_ALL) {
// ... draw frame/box and other static stuff ...
}
if (damage() & (FL_DAMAGE_ALL | 1)) draw_part1();
if (damage() & (FL_DAMAGE_ALL | 2)) draw_part2();
if (damage() & (FL_DAMAGE_ALL | 4)) draw_part3();
}
\endcode
\todo Clarify Fl_Window::damage(uchar) handling - seems confused/wrong?
@ -259,18 +259,18 @@ a pushbutton and also accepts the keystroke \p 'x' to cause the callback:
\code
int MyClass::handle(int event) {
switch(event) {
switch (event) {
case FL_PUSH:
highlight = 1;
redraw();
return 1;
case FL_DRAG: {
int t = Fl::event_inside(this);
if (t != highlight) {
highlight = t;
redraw();
}
int t = Fl::event_inside(this);
if (t != highlight) {
highlight = t;
redraw();
}
}
return 1;
case FL_RELEASE:
if (highlight) {
@ -416,14 +416,16 @@ that a child needs to be drawn. It is fastest if you avoid
drawing anything else in this case:
\code
int MyClass::draw() {
void MyClass::draw() {
Fl_Widget *const*a = array();
if (damage() == FL_DAMAGE_CHILD) { // only redraw some children
for (int i = children(); i --; a ++) update_child(**a);
for (int i = children(); i--; a++) {
update_child(**a);
}
} else { // total redraw
... draw background graphics ...
// ... draw background graphics ...
// now draw all the children atop the background:
for (int i = children_; i --; a ++) {
for (int i = children(); i--; a++) {
draw_child(**a);
draw_outside_label(**a); // you may not need to do this
}