public CCtrl *CtrlFindUnique(CTask *haystack_task,I64 needle_type)
{//Find task ctrl given ctrl_type.
  CCtrl *c;
  c=haystack_task->next_ctrl;
  while (c!=&haystack_task->next_ctrl)
  {
    if (c->type==needle_type)
      return c;
    c=c->next;
  }
  return NULL;
}

U0 CtrlsUpdate(CTask *task)
{
  CCtrl *c;
  c=task->next_ctrl;
  while (c!=&task->next_ctrl)
  {
    if (c->update_derived_vals)
      (*c->update_derived_vals)(c);
    if (c->flags&CTRLF_BORDER)
    {
      c->scrn_left  =gr.pan_text_x+task->pix_left+c->left-FONT_WIDTH;
      c->scrn_right =gr.pan_text_x+task->pix_left+c->right-FONT_WIDTH;
      c->scrn_top   =gr.pan_text_y+task->pix_top+c->top-FONT_HEIGHT;
      c->scrn_bottom=gr.pan_text_y+task->pix_top+c->bottom-FONT_HEIGHT;
    }
    else
    {
      c->scrn_left  =gr.pan_text_x+task->pix_left+c->left;
      c->scrn_right =gr.pan_text_x+task->pix_left+c->right;
      c->scrn_top   =gr.pan_text_y+task->pix_top+c->top;
      c->scrn_bottom=gr.pan_text_y+task->pix_top+c->bottom;
    }
    c=c->next;
  }
}

fp_update_ctrls=&CtrlsUpdate;

Bool CtrlInsideRect(CCtrl *c,I64 x,I64 y)
{//scrn coordinates
  if (c->scrn_left<=x<=c->scrn_right &&
      c->scrn_top<=y<=c->scrn_bottom)
    return TRUE;
  else
    return FALSE;
}

public Bool CtrlInside(CCtrl *c,I64 x,I64 y)
{//Is x,y inside a ctrl?
  if (c->flags&CTRLF_SHOW)
  {
    if (c->inside_ctrl)
      return (*c->inside_ctrl)(c,x,y);
    else
      return CtrlInsideRect(c,x,y);
  }
  else
    return FALSE;
}

U0 DrawCtrls(CTask *task)
{
  CCtrl *c;
  CDC *dc=DCAlias(gr.dc2,task);
  c=task->next_ctrl;
  while (c!=&task->next_ctrl)
  {
    if (c->flags&CTRLF_SHOW)
    {
      if (c->flags&CTRLF_BORDER)
      {
        if (!Bt(&task->display_flags,DISPLAYf_NO_BORDER))
        {
          PUSHFD
          CLI
          while (LBts(&task->task_flags,TASKf_TASK_LOCK))
            PAUSE
            task->win_left--; //Allow drawing on border
          task->win_right++;
          task->win_top--;
          task->win_bottom++;
          WinDerivedValsUpdate(task);
          LBtr(&task->task_flags,TASKf_TASK_LOCK);
          POPFD
          if (c->draw_it)
            (*c->draw_it)(dc,c);
          PUSHFD
          CLI
          while (LBts(&task->task_flags,TASKf_TASK_LOCK))
            PAUSE
            task->win_left++;
          task->win_right--;
          task->win_top++;
          task->win_bottom--;
          WinDerivedValsUpdate(task);
          LBtr(&task->task_flags,TASKf_TASK_LOCK);
          POPFD
        }
      }
      else if (c->draw_it)
        (*c->draw_it)(dc,c);
    }
    c=c->next;
  }
  DCDel(dc);
}

#define WIN_SCROLL_SIZE         8
#define WIN_SCROLL_BORDER_BONUS 4
U0 DrawWinScroll(CDC *dc,CCtrl *c)
{
  CWinScroll *s=c->state;
  if (c->flags&CTRLF_CLICKED)
    dc->color=s->color>>4;
  else
    dc->color=s->color&0xF;
  GrRect(dc,c->left,c->top,c->right-c->left+1,c->bottom-c->top+1);
  if (c->flags&CTRLF_CLICKED)
    dc->color=s->color&0xF;
  else
    dc->color=s->color>>4;
  GrRect(dc,c->left+2,c->top+2,c->right-c->left+1-4,c->bottom-c->top+1-4);
}

U0 WinDerivedScrollValsUpdate(CCtrl *c)
{
  CWinScroll *s=c->state;
  I64 range;
  if (s->max<s->min) s->max=s->min;
  if (s->pos<s->min) s->pos=s->min;
  if (s->pos>s->max) s->pos=s->max;
  s->color=c->win_task->border_attr&0xF^0xF+
           (c->win_task->border_attr&0xF)<<4;
  range=s->max-s->min;
  if (!range) range=1;
  switch (c->type)
  {
  case CTRLT_WIN_HSCROLL:
    c->left  =gr.pan_text_x+FONT_WIDTH-WIN_SCROLL_BORDER_BONUS+
              (s->pos-s->min)*(c->win_task->pix_width+2*WIN_SCROLL_BORDER_BONUS
                               -WIN_SCROLL_SIZE)/range;
    c->right =c->left+WIN_SCROLL_SIZE-1;
    c->top   =gr.pan_text_y+FONT_HEIGHT+
              (FONT_WIDTH-WIN_SCROLL_SIZE)/2+c->win_task->pix_height;
    c->bottom=c->top+WIN_SCROLL_SIZE-1;
    break;
  case CTRLT_WIN_VSCROLL:
    c->left  =gr.pan_text_x+FONT_WIDTH+
              (FONT_WIDTH-WIN_SCROLL_SIZE)/2+c->win_task->pix_width;
    c->right =c->left+WIN_SCROLL_SIZE-1;
    c->top   =gr.pan_text_y+FONT_HEIGHT-WIN_SCROLL_BORDER_BONUS+
              (s->pos-s->min)*(c->win_task->pix_height+
                               2*WIN_SCROLL_BORDER_BONUS-WIN_SCROLL_SIZE)/range;
    c->bottom=c->top+WIN_SCROLL_SIZE-1;
    break;
  }
}

U0 LeftClickHWinScroll(CCtrl *c,I64 x,I64,Bool down)
{
  CTask *task=c->win_task;
  CWinScroll *s=c->state;
  I64 range=task->pix_width+2*WIN_SCROLL_BORDER_BONUS-WIN_SCROLL_SIZE;
  LBts(&s->flags,WSSf_SET_TO_POS);
  s->pos=((x-(FONT_WIDTH-WIN_SCROLL_BORDER_BONUS))
          *(s->max-s->min+1)+range/2)/range+s->min;
  if (down)
    c->flags|=CTRLF_CLICKED;
  else
    c->flags&=~CTRLF_CLICKED;
  if (c->update_derived_vals)
    (*c->update_derived_vals)(c);
}

U0 LeftClickVWinScroll(CCtrl *c,I64,I64 y,Bool down)
{
  CTask *task=c->win_task;
  CWinScroll *s=c->state;
  I64 range=task->pix_height+2*WIN_SCROLL_BORDER_BONUS-WIN_SCROLL_SIZE;
  LBts(&s->flags,WSSf_SET_TO_POS);
  s->pos=((y-(FONT_HEIGHT-WIN_SCROLL_BORDER_BONUS))
          *(s->max-s->min+1)+range/2)/range+s->min;
  if (down)
    c->flags|=CTRLF_CLICKED;
  else
    c->flags&=~CTRLF_CLICKED;
  if (c->update_derived_vals)
    (*c->update_derived_vals)(c);
}

U0 WheelChangeWinScroll(CCtrl *c,I64 delta)
{
  CWinScroll *s=c->state;
  LBts(&s->flags,WSSf_SET_TO_POS);
  s->pos+=delta;
  if (c->update_derived_vals)
    (*c->update_derived_vals)(c);
}

U0 WinScrollsInit(CTask *task)
{
  CCtrl *c;
  if (!CtrlFindUnique(task,CTRLT_WIN_HSCROLL))
  {
    c=CAlloc(sizeof(CCtrl));
    c->win_task=task;
    c->flags=CTRLF_SHOW|CTRLF_BORDER|CTRLF_CAPTURE_LEFT_MS;
    c->type=CTRLT_WIN_HSCROLL;
    c->state=&task->horz_scroll;
    c->update_derived_vals=&WinDerivedScrollValsUpdate;
    c->draw_it=&DrawWinScroll;
    c->left_click=&LeftClickHWinScroll;
    QueIns(c,task->last_ctrl);
  }
  if (!CtrlFindUnique(task,CTRLT_WIN_VSCROLL))
  {
    c=CAlloc(sizeof(CCtrl));
    c->win_task=task;
    c->flags=CTRLF_SHOW|CTRLF_BORDER|CTRLF_CAPTURE_LEFT_MS;
    c->type=CTRLT_WIN_VSCROLL;
    c->state=&task->vert_scroll;
    c->update_derived_vals=&WinDerivedScrollValsUpdate;
    c->draw_it=&DrawWinScroll;
    c->left_click=&LeftClickVWinScroll;
    c->wheel_chg=&WheelChangeWinScroll;
    QueIns(c,task->last_ctrl);
  }
  TaskDerivedValsUpdate(task);
}
#define VIEWANGLES_SPACING      22
#define VIEWANGLES_RANGE        48
#define VIEWANGLES_BORDER       2
#define VIEWANGLES_SNAP         2

U0 DrawViewAnglesCtrl(CDC *dc,CCtrl *c)
{
  I64 i,j;
  CViewAngles *s=c->state;
  dc->color=s->cbd;
  GrRect(dc, c->left,c->top,VIEWANGLES_SPACING*4+3,
         VIEWANGLES_SPACING*2+VIEWANGLES_RANGE);
  dc->color=s->cbg;
  GrRect(dc, c->left+VIEWANGLES_BORDER,c->top+VIEWANGLES_BORDER,
         VIEWANGLES_SPACING*4+3-2*VIEWANGLES_BORDER,
         VIEWANGLES_SPACING*2+VIEWANGLES_RANGE-2*VIEWANGLES_BORDER);
  dc->color=s->cfg;
  GrLine(dc,c->left+VIEWANGLES_SPACING,c->top+VIEWANGLES_SPACING,
         c->left+VIEWANGLES_SPACING,c->top+VIEWANGLES_SPACING+
         VIEWANGLES_RANGE-1);
  GrLine(dc,c->left+2*VIEWANGLES_SPACING+1,c->top+VIEWANGLES_SPACING,
         c->left+2*VIEWANGLES_SPACING+1,c->top+VIEWANGLES_SPACING+
         VIEWANGLES_RANGE-1);
  GrLine(dc,c->left+3*VIEWANGLES_SPACING+2,c->top+VIEWANGLES_SPACING,
         c->left+3*VIEWANGLES_SPACING+2,c->top+VIEWANGLES_SPACING+
         VIEWANGLES_RANGE-1);
  for (i=1; i<VIEWANGLES_RANGE+1; i+=2*VIEWANGLES_SNAP)
  {
    j=2-i/3&1;
    GrLine(dc,c->left+VIEWANGLES_SPACING-j,c->bottom-VIEWANGLES_SPACING-i,
           c->left+VIEWANGLES_SPACING+j,c->bottom
           -VIEWANGLES_SPACING-i);
    GrLine(dc,c->left+2*VIEWANGLES_SPACING+1-j,c->bottom-VIEWANGLES_SPACING-i,
           c->left+2*VIEWANGLES_SPACING+1+j,c->bottom
           -VIEWANGLES_SPACING-i);
    GrLine(dc,c->left+3*VIEWANGLES_SPACING+2-j,c->bottom-VIEWANGLES_SPACING-i,
           c->left+3*VIEWANGLES_SPACING+2+j,c->bottom
           -VIEWANGLES_SPACING-i);
  }
  dc->color=s->cx;
  GrPrint(dc,c->left+VIEWANGLES_SPACING-FONT_WIDTH/2,
          c->top+VIEWANGLES_SPACING-(1+FONT_HEIGHT),"X");
  GrPrint(dc,c->left+VIEWANGLES_SPACING-3*FONT_WIDTH/2,
          c->top+VIEWANGLES_SPACING+VIEWANGLES_RANGE+3,
          "%3d",s->sx*360/VIEWANGLES_RANGE);
  i=c->left+VIEWANGLES_SPACING;
  if (s->sx>VIEWANGLES_RANGE/2)
    j=-VIEWANGLES_RANGE/2+s->sx;
  else
    j=s->sx+VIEWANGLES_RANGE/2;
  j=c->top+VIEWANGLES_SPACING+VIEWANGLES_RANGE-1-j;
  GrRect(dc,i-3,j-2,7,5);
  dc->color=s->cx^8;
  GrRect(dc,i-2,j-1,5,3);
  dc->color=s->cy;
  GrPrint(dc,c->left+2*VIEWANGLES_SPACING+1-FONT_WIDTH/2,
          c->top+VIEWANGLES_SPACING-(1+FONT_HEIGHT),"Y");
  GrPrint(dc,c->left+2*VIEWANGLES_SPACING+1-3*FONT_WIDTH/2,
          c->top+VIEWANGLES_SPACING+VIEWANGLES_RANGE+3,
          "%3d",s->sy*360/VIEWANGLES_RANGE);
  i=c->left+2*VIEWANGLES_SPACING+1;
  if (s->sy>VIEWANGLES_RANGE/2)
    j=-VIEWANGLES_RANGE/2+s->sy;
  else
    j=s->sy+VIEWANGLES_RANGE/2;
  j=c->top+VIEWANGLES_SPACING+VIEWANGLES_RANGE-1-j;
  GrRect(dc,i-3,j-2,7,5);
  dc->color=s->cy^8;
  GrRect(dc,i-2,j-1,5,3);
  dc->color=s->cz;
  GrPrint(dc,c->left+3*VIEWANGLES_SPACING+2-FONT_WIDTH/2,
          c->top+VIEWANGLES_SPACING-(1+FONT_HEIGHT),"Z");
  GrPrint(dc,c->left+3*VIEWANGLES_SPACING+2-3*FONT_WIDTH/2,
          c->top+VIEWANGLES_SPACING+VIEWANGLES_RANGE+3,
          "%3d",s->sz*360/VIEWANGLES_RANGE);
  i=c->left+3*VIEWANGLES_SPACING+2;
  if (s->sz>VIEWANGLES_RANGE/2)
    j=-VIEWANGLES_RANGE/2+s->sz;
  else
    j=s->sz+VIEWANGLES_RANGE/2;
  j=c->top+VIEWANGLES_SPACING+VIEWANGLES_RANGE-1-j;
  GrRect(dc,i-3,j-2,7,5);
  dc->color=s->cz^8;
  GrRect(dc,i-2,j-1,5,3);
}

U0 UpdateDerivedViewAnglesCtrl(CCtrl *c)
{
  CViewAngles *s=c->state;
  c->left=c->win_task->pix_width-(VIEWANGLES_SPACING*4+3);
  c->right=c->left+VIEWANGLES_SPACING*4+3;
  c->top=c->win_task->pix_height-(VIEWANGLES_SPACING*2+VIEWANGLES_RANGE);
  c->bottom=c->top+VIEWANGLES_SPACING*2+VIEWANGLES_RANGE;
  s->sx=ClampI64(RoundI64(s->sx,VIEWANGLES_SNAP),0,VIEWANGLES_RANGE-1);
  s->sy=ClampI64(RoundI64(s->sy,VIEWANGLES_SNAP),0,VIEWANGLES_RANGE-1);
  s->sz=ClampI64(RoundI64(s->sz,VIEWANGLES_SNAP),0,VIEWANGLES_RANGE-1);
  s->ax=2*pi*s->sx/VIEWANGLES_RANGE;
  s->ay=2*pi*s->sy/VIEWANGLES_RANGE;
  s->az=2*pi*s->sz/VIEWANGLES_RANGE;
}

U0 LeftClickViewAngles(CCtrl *c,I64 x,I64 y,Bool)
{
  CViewAngles *s=c->state;
  I64 i;
  i=VIEWANGLES_RANGE-1-(y-(c->top+VIEWANGLES_SPACING));
  if (i>=VIEWANGLES_RANGE/2)
    i-=VIEWANGLES_RANGE/2;
  else
    i+=VIEWANGLES_RANGE/2;
  if (x<c->left+(c->right-c->left)/3)
    s->sx=i;
  else if (x<c->left+2*(c->right-c->left)/3)
    s->sy=i;
  else
    s->sz=i;
  if (c->update_derived_vals)
    (*c->update_derived_vals)(c);
}

public CCtrl *ViewAnglesNew(CTask *task=NULL)
{//Create view angle ctrl. See ::/Demo/Graphics/Shading.HC.
  CCtrl *c;
  CViewAngles *s;
  if (!task) task=Fs;
  if (!(c=CtrlFindUnique(task,CTRLT_VIEWING_ANGLES)))
  {
    s=CAlloc(sizeof(CViewAngles),task);
    c=CAlloc(sizeof(CCtrl));
    s->cbd=BLUE;
    s->cbg=LTBLUE;
    s->cfg=BLACK;
    s->cx=LTGREEN;
    s->cy=GREEN;
    s->cz=LTGREEN;
    c->win_task=task;
    c->flags=CTRLF_SHOW|CTRLF_CAPTURE_LEFT_MS;
    c->type=CTRLT_VIEWING_ANGLES;
    c->state=s;
    c->draw_it=&DrawViewAnglesCtrl;
    c->left_click=&LeftClickViewAngles;
    c->update_derived_vals=&UpdateDerivedViewAnglesCtrl;
    QueIns(c,task->last_ctrl);
    TaskDerivedValsUpdate(task);
  }
  return c;
}

public U0 ViewAnglesDel(CTask *task=NULL)
{//Free view angle ctrl.
  CCtrl *c;
  if (!task) task=Fs;
  if (c=CtrlFindUnique(task,CTRLT_VIEWING_ANGLES))
  {
    QueRem(c);
    Free(c->state);
    Free(c);
  }
}