pygo/sgc/widgets/radio_button.py

#!/usr/bin/env python

# Copyright (C) 2012  Michael Rochester, Sam Bull

"""
Radio Button, allows the user to select a single option from a group.

"""

import pygame.mouse
from pygame.locals import *

from _locals import *
from _locals import focus
from base_widget import Simple

class Radio(Simple):

    """
    A selectable radio button.

    Attributes:
      groups: A dictionary containing the active radio button or ``None`` for
          each radio group. Key is ``str`` containing the name of the group.
      selected: True if widget is the currently selected radio button in
          it's group.

    Images:
      'image': The default, inactive button state.
      'over': The image used when the cursor is hovering over the button.
      'active': The image used for the active button in a group
          (if applicable).

    """

    _can_focus = True
    _available_images = ("over", "active")
    _settings_default = {"group": None, "label": "", "col": (118, 45, 215),
                         "label_col": Font.col, "radius": 7}

    _over_state = False
    _draw_rect = False

    groups = {}
    _order = {}

    def _config(self, **kwargs):
        """
          group: ``str`` Name of the group for widget to be added to.
          label: ``str`` Text to be displayed to the right of the widget.
          active: ``True`` Makes this the active radio button for it's group.
          col: ``tuple`` (r,g,b) The colour to be used for the 'over' image
              if not using a custom image.
          label_col: ``tuple`` (r,g,b) The colour for the label text.
          radius: ``int`` Radius of the button if not using a custom image.

        """
        if "group" in kwargs:
            if kwargs["group"] not in self.groups:
                self.groups[kwargs["group"]] = None
                self._order[kwargs["group"]] = []
            self._settings["group"] = kwargs["group"]
            self._order[self._settings["group"]].append(self)
        if "label" in kwargs:
            self._settings["label"] = kwargs["label"]
        if "col" in kwargs:
            self._settings["col"] = kwargs["col"]
        if "label_col" in kwargs:
            self._settings["label_col"] = kwargs["label_col"]
        if "radius" in kwargs:
            self._settings["radius"] = kwargs["radius"]
        assert self._settings["group"] is not None
        if "active" in kwargs:
            self._draw()
            self._activate()

    def _draw(self, draw):
        r = self._settings["radius"]
        # Render text
        label = Simple(Font["widget"].render(self._settings["label"], True,
                                             self._settings["label_col"]))
        if not hasattr(self, "image"):
            self._create_base_images((r*2 + 10 + label.rect.w,
                                      max(label.rect.height, r*2)))

        pos = (r, self.rect.h/2)
        # Background circles
        draw.circle(self._images["image"], (255,255,255), pos, r)
        draw.circle(self._images["over"], self._settings["col"], pos, r)
        # Border circles
        draw.circle(self._images["image"], (0,0,1), pos, r, 1)
        draw.circle(self._images["over"], (0,0,1), pos, r, 1)
        # Central dot for 'active' state
        draw.circle(self._images["active"],(0,0,1), pos, int(r/1.5))

        label.rect.midleft = (r*2 + 10, pos[1])
        self._images["image"].blit(label.image, label.pos)
        self._images["over"].blit(label.image, label.pos)
        self._draw_button()

    def update(self, time):
        """Update the radio button each frame."""
        if self.rect_abs.collidepoint(pygame.mouse.get_pos()):
            if not self._over_state:
                # Draw over state
                self._over_state = True
                self._draw_button()
        elif self._over_state:
            # Draw normal state
            self._over_state = False
            self._draw_button()

    def _event(self, event):
        if event.type == MOUSEBUTTONUP and event.button == 1:
            if self.rect_abs.collidepoint(event.pos):
                self._activate()
        elif event.type == KEYDOWN:
            def focus_change(diff):
                next_widget = order[order.index(widget) + diff]
                next_widget._activate()
                if self._parent:
                    self._parent._focus.add(1, next_widget)
                else:
                    focus.add(1, next_widget)
            order = self._order[self._settings["group"]]
            widget = self.groups[self._settings["group"]]
            if event.key == K_UP and order.index(widget) > 0:
                focus_change(-1)
            elif event.key == K_DOWN and order.index(widget) < len(order)-1:
                focus_change(1)
        elif event.type == KEYUP:
            if event.key in (K_SPACE, K_RETURN):
                self._activate()

    def _focus_enter(self, focus):
        """Draw rectangle when focus is gained from keyboard."""
        if focus == 1:
            self._draw_rect = True
            self._draw_button()

    def _focus_exit(self):
        """Stop drawing rectangle when focus is lost."""
        self._draw_rect = False
        self._draw_button()

    def _draw_button(self):
        """Draw the button."""
        if not self._over_state:
            self.image = self._images["image"].copy()
        else:
            self.image = self._images["over"].copy()
        if self.groups[self._settings["group"]] is self:
            self.image.blit(self._images["active"], (0,0))
        # Draw dotted rectangle to show keyboard focus
        if self._draw_rect:
            self._dotted_rect()

    def _activate(self):
        """Reset drawing of new and previous widget."""
        old = self.groups[self._settings["group"]]
        self.groups[self._settings["group"]] = self
        if old is not None: old._draw_button()
        self._draw_button()

    def clear(self, group=None):
        """
        Clear a group so no radio button is selected.

        Args:
          group: ``str`` Group name to clear. Clear this widget's group if None.

        """
        if group is None: group = self._settings["group"]
        old = self.groups[group]
        self.groups[group] = None
        if old is not None: old._draw_button()

    @property
    def selected(self):
        return self is self.groups[self._settings["group"]]