ref: cbe4b116989c0bfec49b9ae7a1d9a85ead6648ae
dir: /sys/src/libdraw/emenuhit.c/
#include <u.h>
#include <libc.h>
#include <draw.h>
#include <event.h>
enum
{
Margin = 4, /* outside to text */
Border = 2, /* outside to selection boxes */
Blackborder = 2, /* width of outlining border */
Vspacing = 2, /* extra spacing between lines of text */
Maxunscroll = 25, /* maximum #entries before scrolling turns on */
Nscroll = 20, /* number entries in scrolling part */
Scrollwid = 14, /* width of scroll bar */
Gap = 4, /* between text and scroll bar */
};
static Image *menutxt;
static Image *back;
static Image *high;
static Image *bord;
static Image *text;
static Image *htext;
static
void
menucolors(void)
{
/* Main tone is greenish, with negative selection */
back = allocimagemix(display, DPalegreen, DWhite);
high = allocimage(display, Rect(0,0,1,1), CMAP8, 1, DDarkgreen); /* dark green */
bord = allocimage(display, Rect(0,0,1,1), CMAP8, 1, DMedgreen); /* not as dark green */
if(back==nil || high==nil || bord==nil)
goto Error;
text = display->black;
htext = back;
return;
Error:
freeimage(back);
freeimage(high);
freeimage(bord);
back = display->white;
high = display->black;
bord = display->black;
text = display->black;
htext = display->white;
}
/*
* r is a rectangle holding the text elements.
* return the rectangle, including its black edge, holding element i.
*/
static Rectangle
menurect(Rectangle r, int i)
{
if(i < 0)
return Rect(0, 0, 0, 0);
r.min.y += (font->height+Vspacing)*i;
r.max.y = r.min.y+font->height+Vspacing;
return insetrect(r, Border-Margin);
}
/*
* r is a rectangle holding the text elements.
* return the element number containing p.
*/
static int
menusel(Rectangle r, Point p)
{
if(!ptinrect(p, r))
return -1;
return (p.y-r.min.y)/(font->height+Vspacing);
}
static void
paintitem(Menu *menu, Rectangle textr, int off, int i, int highlight, Image *save, Image *restore)
{
char *item;
Rectangle r;
Point pt;
if(i < 0)
return;
r = menurect(textr, i);
if(restore){
draw(screen, r, restore, nil, restore->r.min);
return;
}
if(save)
draw(save, save->r, screen, nil, r.min);
item = menu->item? menu->item[i+off] : (*menu->gen)(i+off);
pt.x = (textr.min.x+textr.max.x-stringwidth(font, item))/2;
pt.y = textr.min.y+i*(font->height+Vspacing);
draw(screen, r, highlight? high : back, nil, pt);
string(screen, pt, highlight? htext : text, pt, font, item);
}
/*
* menur is a rectangle holding all the highlightable text elements.
* track mouse while inside the box, return what's selected when button
* is raised, -1 as soon as it leaves box.
* invariant: nothing is highlighted on entry or exit.
*/
static int
menuscan(Menu *menu, int but, Mouse *m, Rectangle textr, int off, int lasti, Image *save)
{
int i;
paintitem(menu, textr, off, lasti, 1, save, nil);
flushimage(display, 1); /* in case display->locking is set */
*m = emouse();
while(m->buttons & (1<<(but-1))){
flushimage(display, 1); /* in case display->locking is set */
*m = emouse();
i = menusel(textr, m->xy);
if(i != -1 && i == lasti)
continue;
paintitem(menu, textr, off, lasti, 0, nil, save);
if(i == -1)
return i;
lasti = i;
paintitem(menu, textr, off, lasti, 1, save, nil);
}
return lasti;
}
static void
menupaint(Menu *menu, Rectangle textr, int off, int nitemdrawn)
{
int i;
draw(screen, insetrect(textr, Border-Margin), back, nil, ZP);
for(i = 0; i<nitemdrawn; i++)
paintitem(menu, textr, off, i, 0, nil, nil);
}
static void
menuscrollpaint(Rectangle scrollr, int off, int nitem, int nitemdrawn)
{
Rectangle r;
draw(screen, scrollr, back, nil, ZP);
r.min.x = scrollr.min.x;
r.max.x = scrollr.max.x;
r.min.y = scrollr.min.y + (Dy(scrollr)*off)/nitem;
r.max.y = scrollr.min.y + (Dy(scrollr)*(off+nitemdrawn))/nitem;
if(r.max.y < r.min.y+2)
r.max.y = r.min.y+2;
border(screen, r, 1, bord, ZP);
if(menutxt == 0)
menutxt = allocimage(display, Rect(0, 0, 1, 1), CMAP8, 1, DDarkgreen);
if(menutxt)
draw(screen, insetrect(r, 1), menutxt, nil, ZP);
}
int
emenuhit(int but, Mouse *m, Menu *menu)
{
int i, nitem, nitemdrawn, maxwid, lasti, off, noff, wid, screenitem;
int scrolling;
Rectangle r, menur, sc, textr, scrollr;
Image *b, *save;
Point pt;
char *item;
if(back == nil)
menucolors();
sc = screen->clipr;
replclipr(screen, 0, screen->r);
maxwid = 0;
for(nitem = 0;
item = menu->item? menu->item[nitem] : (*menu->gen)(nitem);
nitem++){
i = stringwidth(font, item);
if(i > maxwid)
maxwid = i;
}
if(menu->lasthit<0 || menu->lasthit>=nitem)
menu->lasthit = 0;
screenitem = (Dy(screen->r)-10)/(font->height+Vspacing);
if(nitem>Maxunscroll || nitem>screenitem){
scrolling = 1;
nitemdrawn = Nscroll;
if(nitemdrawn > screenitem)
nitemdrawn = screenitem;
wid = maxwid + Gap + Scrollwid;
off = menu->lasthit - nitemdrawn/2;
if(off < 0)
off = 0;
if(off > nitem-nitemdrawn)
off = nitem-nitemdrawn;
lasti = menu->lasthit-off;
}else{
scrolling = 0;
nitemdrawn = nitem;
wid = maxwid;
off = 0;
lasti = menu->lasthit;
}
r = insetrect(Rect(0, 0, wid, nitemdrawn*(font->height+Vspacing)), -Margin);
r = rectsubpt(r, Pt(wid/2, lasti*(font->height+Vspacing)+font->height/2));
r = rectaddpt(r, m->xy);
pt = ZP;
if(r.max.x>screen->r.max.x)
pt.x = screen->r.max.x-r.max.x;
if(r.max.y>screen->r.max.y)
pt.y = screen->r.max.y-r.max.y;
if(r.min.x<screen->r.min.x)
pt.x = screen->r.min.x-r.min.x;
if(r.min.y<screen->r.min.y)
pt.y = screen->r.min.y-r.min.y;
menur = rectaddpt(r, pt);
textr.max.x = menur.max.x-Margin;
textr.min.x = textr.max.x-maxwid;
textr.min.y = menur.min.y+Margin;
textr.max.y = textr.min.y + nitemdrawn*(font->height+Vspacing);
if(scrolling){
scrollr = insetrect(menur, Border);
scrollr.max.x = scrollr.min.x+Scrollwid;
}else
scrollr = Rect(0, 0, 0, 0);
b = allocimage(display, menur, screen->chan, 0, 0);
if(b == 0)
b = screen;
draw(b, menur, screen, nil, menur.min);
draw(screen, menur, back, nil, ZP);
border(screen, menur, Blackborder, bord, ZP);
save = allocimage(display, menurect(textr, 0), screen->chan, 0, -1);
r = menurect(textr, lasti);
if(pt.x || pt.y)
emoveto(divpt(addpt(r.min, r.max), 2));
menupaint(menu, textr, off, nitemdrawn);
if(scrolling)
menuscrollpaint(scrollr, off, nitem, nitemdrawn);
while(m->buttons & (1<<(but-1))){
lasti = menuscan(menu, but, m, textr, off, lasti, save);
if(lasti >= 0)
break;
while(!ptinrect(m->xy, textr) && (m->buttons & (1<<(but-1)))){
if(scrolling && ptinrect(m->xy, scrollr)){
noff = ((m->xy.y-scrollr.min.y)*nitem)/Dy(scrollr);
noff -= nitemdrawn/2;
if(noff < 0)
noff = 0;
if(noff > nitem-nitemdrawn)
noff = nitem-nitemdrawn;
if(noff != off){
off = noff;
menupaint(menu, textr, off, nitemdrawn);
menuscrollpaint(scrollr, off, nitem, nitemdrawn);
}
}
flushimage(display, 1); /* in case display->locking is set */
*m = emouse();
}
}
draw(screen, menur, b, nil, menur.min);
if(b != screen)
freeimage(b);
freeimage(save);
replclipr(screen, 0, sc);
if(lasti >= 0){
menu->lasthit = lasti+off;
return menu->lasthit;
}
return -1;
}