Initial checkin: supports adjustColumnWidths

diff --git a/xsl/extensions/xsltproc/python/docbook.py b/xsl/extensions/xsltproc/python/docbook.py
new file mode 100644 (file)
index 0000000..26096d5
--- /dev/null
+++ b/xsl/extensions/xsltproc/python/docbook.py
@@ -0,0 +1,208 @@
+#!/usr/bin/python -u
+
+# THIS IS ALPHA CODE AND IS NOT COMPLETE!
+
+import sys
+import string
+import libxml2
+import libxslt
+import re
+import math
+
+# Some globals
+pixelsPerInch = 96.0
+unitHash = { 'in': pixelsPerInch,
+             'cm': pixelsPerInch / 2.54,
+             'mm': pixelsPerInch / 25.4,
+             'pc': (pixelsPerInch / 72.0) * 12,
+             'pt': pixelsPerInch / 72.0,
+             'px': 1 }
+
+# ======================================================================
+
+def adjustColumnWidths(ctx, nodeset):
+    #
+    # Small check to verify the context is correcly accessed
+    #
+    try:
+        pctxt = libxslt.xpathParserContext(_obj=ctx)
+        ctxt = pctxt.context()
+        tctxt = ctxt.transformContext()
+    except:
+        pass
+
+    # Get the nominal table width
+    varString = tctxt.variableLookup("nominal.table.width", None);
+    if varString == None:
+        nominalWidth = 6 * pixelsPerInch;
+    else:
+        nominalWidth = convertLength(varString);
+
+    varString = tctxt.variableLookup("table.width", None);
+    if varString == None:
+        tableWidth = "100%"
+    else:
+        tableWidth = varString
+
+    foStylesheet = (tctxt.variableLookup("stylesheet.result.type", None) == "fo");
+
+    relTotal = 0
+    relParts = []
+
+    absTotal = 0
+    absParts = []
+
+    colgroup = libxml2.xmlNode(_obj = nodeset[0])
+    col = colgroup.children;
+    while col != None:
+        width = col.prop("width")
+        relPart = 0.0;
+        absPart = 0.0;
+        starPos = string.find(width, "*");
+        if starPos >= 0:
+            relPart, absPart = string.split(width, "*", 2)
+            relPart = float(relPart);
+            relTotal = relTotal + float(relPart)
+        else:
+            absPart = width
+
+        pixels = convertLength(absPart);
+        absTotal = absTotal + pixels;
+
+        relParts.append(relPart);
+        absParts.append(pixels);
+
+        col = col.next
+
+    # Ok, now we have the relative widths and absolute widths in
+    # two parallel arrays.
+    #
+    # - If there are no relative widths, output the absolute widths
+    # - If there are no absolute widths, output the relative widths
+    # - If there are a mixture of relative and absolute widths,
+    #   - If the table width is absolute, turn these all into absolute
+    #     widths.
+    #   - If the table width is relative, turn these all into absolute
+    #     widths in the nominalWidth and then turn them back into
+    #     percentages.
+
+    widths = [];
+
+    if relTotal == 0:
+        for absPart in absParts:
+            if foStylesheet:
+                inches = absPart / pixelsPerInch
+                widths.append("%4.2fin" % inches)
+            else:
+                widths.append("%d" % absPart)
+    elif absTotal == 0:
+        for relPart in relParts:
+            rel = relPart / relTotal * 100;
+            widths.append(rel);
+        widths = correctRoundingError(widths)
+    else:
+        pixelWidth = nominalWidth;
+        if string.find(tableWidth, "%") < 0:
+            pixelWidth = convertLength(tableWidth);
+
+        if pixelWidth <= absTotal:
+            print "Table is wider than table width"
+        else:
+            pixelWidth = pixelWidth - absTotal;
+
+        absTotal = 0
+        for count in range(len(relParts)):
+            rel = relParts[count] / relTotal * pixelWidth
+            relParts[count] = rel + absParts[count]
+            absTotal = absTotal + rel + absParts[count]
+
+        if string.find(tableWidth, "%") < 0:
+            for count in range(len(relParts)):
+                if foStylesheet:
+                    pixels = relParts[count]
+                    inches = pixels / pixelsPerInch
+                    widths.append("%4.2fin" % inches)
+                else:
+                    widths.append(relParts[count])
+        else:
+            for count in range(len(relParts)):
+                rel = relParts[count] / absTotal * 100
+                widths.append("%d%%" % rel)
+
+    # Danger, Will Robinson! In-place modification of the result tree!
+    # Side-effect free? We don' need no steenkin' side-effect free!
+    count = 0
+    col = colgroup.children
+    while col != None:
+        col.setProp("width", widths[count])
+        count = count+1
+        col = col.next
+
+    return [colgroup]
+
+def convertLength(length):
+    # Given "3.4in" return the width in pixels
+    global pixelsPerInch
+    global unitHash
+
+    m = re.search('([+-]?[\d\.]+)(\S+)', length)
+    if m != None and m.lastindex > 1:
+        unit = pixelsPerInch;
+        if unitHash.has_key(m.group(2)):
+            unit = unitHash[m.group(2)];
+        else:
+            print "Unrecognized length: " + m.group(2)
+
+        pixels = unit * float(m.group(1))
+    else:
+        pixels = 0
+
+    return pixels
+
+def correctRoundingError(floatWidths):
+    # The widths are currently floating point numbers, we have to truncate
+    # them back to integers and then distribute the error so that they sum
+    # to exactly 100%.
+    totalWidth = 0
+    widths = [];
+    for width in floatWidths:
+        width = math.floor(width)
+        widths.append(width)
+        totalWidth = totalWidth + math.floor(width)
+
+    totalError = 100 - totalWidth
+    columnError = totalError / len(widths)
+    error = 0
+    for count in range(len(widths)):
+        width = widths[count]
+        error = error + columnError
+        if error >= 1.0:
+            adj = math.floor(error);
+            error = error - adj;
+            widths[count] = "%d%%" % (width + adj)
+        else:
+            widths[count] = "%d%%" % width
+
+    return widths
+
+# ======================================================================
+# Random notes...
+
+#once you have a node which is a libxml2 python xmlNode wrapper all common
+#operations are possible:
+#   .children .last .parent .next .prev .doc for navigation
+#   .content .type for introspection
+#   .prop("attribute_name") to lookup attribute values
+
+#    # Now make a nodeset to return
+#    # Danger, Will Robinson! This creates a memory leak!
+#    newDoc = libxml2.newDoc("1.0");
+#    newColGroup = newDoc.newDocNode(None, "colgroup", None);
+#    newDoc.addChild(newColGroup);
+#    col = colgroup.children
+#    while col != None:
+#        newCol = newDoc.newDocNode(None, "col", None);
+#        newCol.copyPropList(col);
+#        newCol.setProp("width", "4")
+#        newColGroup.addChild(newCol)
+#        col = col.next