#--------------------------------------------------------------------------
#
#   PyGUI - Palette View - Generic
#
#--------------------------------------------------------------------------

from GUI import export
from GUI.Properties import overridable_property
from GUI import StdColors, GridView
from GUI.GUtils import splitdict

class PaletteView(GridView):
    """A GridView whose cells are identified by a linear index from
    left to right and top to bottom. Also provides support for
    highlighting one or more selected cells."""
    
    num_items = overridable_property('num_items',
        "Total number of items")
        
    items_per_row = overridable_property('items_per_row',
        "Number of items displayed in one row")
    
    highlight_style = overridable_property('highlight_style',
        "Style of selection highlighting")
        
    highlight_color = overridable_property('highlight_color',
        "Color of selection highlighting")
        
    highlight_thickness = overridable_property('highlight_thickness',
        "Width of selection highlighting for 'frame' highlight mode")
    
    _highlight_style = 'fill'
    _highlight_color = StdColors.selection_backcolor
    _highlight_thickness = 4
    
    def __init__(self, num_items, items_per_row, cell_size,
            scrolling = '', **kwds):
        base_kwds = splitdict(kwds, 'border', scrolling = '')
        GridView.__init__(self, num_rows = 0, num_columns = 0, 
            cell_size = cell_size, **base_kwds)
        self._num_items = num_items
        self._items_per_row = items_per_row
        self._update_num_rows_and_columns()
        ew, eh = self.extent
        if not self.hscrolling:
            self.content_width = ew
        if not self.vscrolling:
            self.content_height = eh
        self.set(**kwds)
    
    def get_num_items(self):
        return self._num_items
    
    def set_num_items(self, n):
        self._num_items = n
        self._update_num_rows_and_columns()
    
    def get_items_per_row(self):
        return self.num_columns
    
    def set_items_per_row(self, n):
        self._items_per_row = n
        self._update_num_rows_and_columns()
    
    def _update_num_rows_and_columns(self):
        nc = self._items_per_row
        nr = (self._num_items + nc - 1) // nc
        self._num_columns = nc
        self._num_rows = nr
        self._update_extent()
    
    def get_highlight_style(self):
        return self._highlight_style
    
    def set_highlight_style(self, x):
        self._highlight_style = x
    
    def get_highlight_color(self):
        return self._highlight_color
    
    def set_highlight_color(self, x):
        self._highlight_color = x
    
    def get_highlight_color(self):
        return self._highlight_color
    
    def set_highlight_color(self, x):
        self._highlight_color = x
    
    def item_no_of_cell(self, row, col):
        i = row * self._items_per_row + col
        if 0 <= i < self._num_items:
            return i
    
    def cell_of_item_no(self, item_no):
        if 0 <= item_no < self._num_items:
            return divmod(item_no, self._items_per_row)
    
    def item_rect(self, item_no):
        cell = self.cell_of_item_no(item_no)
        if cell:
            return self.cell_rect(*cell)
    
    def draw_cell(self, canvas, row, col, rect):
        i = self.item_no_of_cell(row, col)
        if i is not None:
            highlight = self.item_is_selected(i)
            self.draw_item_and_highlight(canvas, i, rect, highlight)
    
    def draw_item_and_highlight(self, canvas, item_no, rect, highlight):
        """Draw the specified item, with selection highlighting if highlight
        is true."""
        if highlight:
            style = self.highlight_style
            if style:
                canvas.gsave()
                if style == 'fill':
                    canvas.fillcolor = self.highlight_color
                    canvas.fill_rect(rect)
                else:
                    canvas.pencolor = self.highlight_color
                    canvas.pensize = self.highlight_thickness
                    canvas.frame_rect(rect)
                canvas.grestore()
        self.draw_item(canvas, item_no, rect)
    
    def draw_item(self, canvas, item_no, rect):
        """Should draw the specified item in the given rect."""
        pass

    def click_cell(self, row, col, event):
        i = self.item_no_of_cell(row, col)
        if i is not None:
            self.click_item(i, event)
    
    def click_item(self, item_no, event):
        """Called when a mouse_down event has occurred in the indicated item."""
        pass
    
    def item_is_selected(self, item_no):
        """Should return true if the indicated item is to be drawn highlighted."""
        return False

export(PaletteView)