fancytext.py

Wxpython Implemented on Windows CE, Source code

# 12/02/2003 - Jeff Grimmett ([e-mail])
#
# o Updated for 2.5 compatability.
#

"""
FancyText -- methods for rendering XML specified text

This module exports four main methods::

    def GetExtent(str, dc=None, enclose=True)
    def GetFullExtent(str, dc=None, enclose=True)
    def RenderToBitmap(str, background=None, enclose=True)
    def RenderToDC(str, dc, x, y, enclose=True)

In all cases, 'str' is an XML string. Note that start and end tags are
only required if *enclose* is set to False. In this case the text
should be wrapped in FancyText tags.

In addition, the module exports one class::

    class StaticFancyText(self, window, id, text, background, ...)

This class works similar to StaticText except it interprets its text
as FancyText.

The text can support superscripts and subscripts, text in different
sizes, colors, styles, weights and families. It also supports a
limited set of symbols, currently *times*, *infinity*, *angle* as well
as greek letters in both upper case (*Alpha* *Beta*... *Omega*) and
lower case (*alpha* *beta*... *omega*).

>>> frame = wx.Frame(wx.NULL, -1, "FancyText demo", wx.DefaultPosition)
>>> sft = StaticFancyText(frame, -1, testText, wx.Brush("light grey", wx.SOLID))
>>> frame.SetClientSize(sft.GetSize())
>>> didit = frame.Show()
>>> from guitest import PauseTests; PauseTests()

"""

# Copyright 2001-2003 Timothy Hochberg
# Use as you see fit. No warantees, I cannot be held responsible, etc.

import copy
import math
import sys

import wx
import xml.parsers.expat

__all__ = "GetExtent", "GetFullExtent", "RenderToBitmap", "RenderToDC", "StaticFancyText"

if sys.platform == "win32":
    _greekEncoding = str(wx.FONTENCODING_CP1253)
else:
    _greekEncoding = str(wx.FONTENCODING_ISO8859_7)

_families = {"fixed" : wx.FIXED, "default" : wx.DEFAULT, "decorative" : wx.DECORATIVE, "roman" : wx.ROMAN,
                "script" : wx.SCRIPT, "swiss" : wx.SWISS, "modern" : wx.MODERN}
_styles = {"normal" : wx.NORMAL, "slant" : wx.SLANT, "italic" : wx.ITALIC}
_weights = {"normal" : wx.NORMAL, "light" : wx.LIGHT, "bold" : wx.BOLD}

# The next three classes: Renderer, SizeRenderer and DCRenderer are
# what you will need to override to extend the XML language. All of
# the font stuff as well as the subscript and superscript stuff are in 
# Renderer.

_greek_letters = ("alpha", "beta", "gamma", "delta", "epsilon",  "zeta",
                 "eta", "theta", "iota", "kappa", "lambda", "mu", "nu",
                 "xi", "omnikron", "pi", "rho", "altsigma", "sigma", "tau", "upsilon",
                 "phi", "chi", "psi", "omega")

def iround(number):
    return int(round(number))
    
def iceil(number):
    return int(math.ceil(number))

class Renderer:
    """Class for rendering XML marked up text.

    See the module docstring for a description of the markup.

    This class must be subclassed and the methods the methods that do
    the drawing overridden for a particular output device.

    """
    defaultSize = None
    defaultFamily = wx.DEFAULT
    defaultStyle = wx.NORMAL
    defaultWeight = wx.NORMAL
    defaultEncoding = None
    defaultColor = "black"

    def __init__(self, dc=None, x=0, y=None):
        if dc == None:
            dc = wx.MemoryDC()
        self.dc = dc
        self.offsets = [0]
        self.fonts = [{}]
        self.width = self.height = 0
        self.x = x
        self.minY = self.maxY = self._y = y
        if Renderer.defaultSize is None:
            Renderer.defaultSize = wx.NORMAL_FONT.GetPointSize()
        if Renderer.defaultEncoding is None:
            Renderer.defaultEncoding = wx.Font_GetDefaultEncoding()
        
    def getY(self):
        if self._y is None:
            self.minY = self.maxY = self._y = self.dc.GetTextExtent("M")[1]
        return self._y
    def setY(self, value):
        self._y = y
    y = property(getY, setY)
        
    def startElement(self, name, attrs):
        method = "start_" + name
        if not hasattr(self, method):
            raise ValueError("XML tag '%s' not supported" % name)
        getattr(self, method)(attrs)

    def endElement(self, name):
        methname = "end_" + name
        if hasattr(self, methname):
            getattr(self, methname)()
        elif hasattr(self, "start_" + name):
            pass
        else:
            raise ValueError("XML tag '%s' not supported" % methname)
        
    def characterData(self, data):
        self.dc.SetFont(self.getCurrentFont())
        for i, chunk in enumerate(data.split('\n')):
            if i:
                self.x = 0
                self.y = self.mayY = self.maxY + self.dc.GetTextExtent("M")[1]
            if chunk:
                width, height, descent, extl = self.dc.GetFullTextExtent(chunk)
                self.renderCharacterData(data, iround(self.x), iround(self.y + self.offsets[-1] - height + descent))
            else:
                width = height = descent = extl = 0
            self.updateDims(width, height, descent, extl)

    def updateDims(self, width, height, descent, externalLeading):
        self.x += width
        self.width = max(self.x, self.width)
        self.minY = min(self.minY, self.y+self.offsets[-1]-height+descent)
        self.maxY = max(self.maxY, self.y+self.offsets[-1]+descent)
        self.height = self.maxY - self.minY

    def start_FancyText(self, attrs):
        pass
    start_wxFancyText = start_FancyText # For backward compatibility

    def start_font(self, attrs):
        for key, value in attrs.items():
            if key == "size":
                value = int(value)
            elif key == "family":
                value = _families[value]
            elif key == "style":
                value = _styles[value]
            elif key == "weight":
                value = _weights[value]
            elif key == "encoding":
                value = int(value)
            elif key == "color":
                pass
            else:
                raise ValueError("unknown font attribute '%s'" % key)
            attrs[key] = value
        font = copy.copy(self.fonts[-1])
        font.update(attrs)
        self.fonts.append(font)

    def end_font(self):
        self.fonts.pop()

    def start_sub(self, attrs):
        if attrs.keys():
            raise ValueError("<sub> does not take attributes")
        font = self.getCurrentFont()
        self.offsets.append(self.offsets[-1] + self.dc.GetFullTextExtent("M", font)[1]*0.5)
        self.start_font({"size" : font.GetPointSize() * 0.8})

    def end_sub(self):
        self.fonts.pop()
        self.offsets.pop()

    def start_sup(self, attrs):
        if attrs.keys():
            raise ValueError("<sup> does not take attributes")
        font = self.getCurrentFont()
        self.offsets.append(self.offsets[-1] - self.dc.GetFullTextExtent("M", font)[1]*0.3)
        self.start_font({"size" : font.GetPointSize() * 0.8})

    def end_sup(self):
        self.fonts.pop()
        self.offsets.pop()        

    def getCurrentFont(self):
        font = self.fonts[-1]
        return wx.Font(font.get("size", self.defaultSize),
                       font.get("family", self.defaultFamily),
                       font.get("style", self.defaultStyle),
                       font.get("weight",self.defaultWeight),
                       False, "",
                       font.get("encoding", self.defaultEncoding))

    def getCurrentColor(self):
        font = self.fonts[-1]
        return wx.TheColourDatabase.FindColour(font.get("color", self.defaultColor))
        
    def getCurrentPen(self):
        return wx.Pen(self.getCurrentColor(), 1, wx.SOLID)
        
    def renderCharacterData(self, data, x, y):
        raise NotImplementedError()


def _addGreek():
    alpha = 0xE1
    Alpha = 0xC1
    def end(self):
        pass
    for i, name in enumerate(_greek_letters):
        def start(self, attrs, code=chr(alpha+i)):
            self.start_font({"encoding" : _greekEncoding})
            self.characterData(code)
            self.end_font()
        setattr(Renderer, "start_%s" % name, start)