lay groundwork for variable-width characters; document problems

--HG--
branch : pmacs2

IDEAS

@@ -1,3 +1,22 @@
+2010/4/27:
+
+It would be awesome to actually handle tabs correctly (e.g. how emacs or vim
+does); that is, instead of substituting N whitespace characters for each tab
+it would just handle seeing tabs correctly. There are some problems doing this:
+
+  1. render objects store the X coordinate to write to; this needs to be
+     calculated if characters are variable-width (easy to fix)
+  2. buffer needs to stop munging/de-munging lines (easy to fix)
+  3. draw_slot() needs to keep track of the X offset when drawing (easy)
+  4. map_point() needs to be fixed so that logical cursor position gets
+     translated correctly (e.g. for x=1, line="\tfoo\n", vx=4) (medium)
+  5. fix all the navigation and cursor positioning code in window.py (hard)
+  6. find all the other places where len(line) gets used for drawing (ugh)
+
+Each time I embark on this I get a little farther before giving up. At this
+point it's a race to see whether I fix indenting for "munged" lines (so that
+"\t  \tfoo" and "    foo" indent the same) or actually fix all these problems.
+
 2009/10/21:
 
 More reasonable:

application.py

@@ -786,17 +786,21 @@ class Application(object):
         swidth = slot.width - w.mode.lmargin - w.mode.rmargin
         blen   = len(w.buffer.lines)
         count  = w.mode.header
-        (x, y) = w.first.xy()
+        x, y   = w.first.xy()
-        (vy, vx) = (None, None)
+        vy, vx = None, None
+
         while count < slot.height:
+            line = w.buffer.lines[y]
+            l = len(line) + line.count('\t') * (w.mode.tabwidth - 1)
+
             if p.y == y and p.x >= x and p.x <= x + swidth:
                 vy, vx = slot.y_offset + count, p.x - x + w.mode.lmargin
-                if vx == swidth and p.x < len(w.buffer.lines[y]):
+                if vx == swidth and p.x < l:
                     vx = 0
                     vy += 1
                 break
                     
-            if y >= blen or x + swidth >= len(w.buffer.lines[y]):
+            if y >= blen or x + swidth >= l:
                 x = 0
                 y += 1
             else:
@@ -942,7 +946,8 @@ class Application(object):
                 k = 0
                 for rstr in rstrs[j]:
                     rstr.draw(self.win, slot.y_offset + j, slot.x_offset + k, slot.width)
-                    k += len(rstr.string)
+                    #k += len(rstr.string)
+                    k += rstr.width(w)
 
         # draw the actual slot
         self._draw_slot(i)
@@ -1001,17 +1006,23 @@ class Application(object):
             for j in xrange(k, len(rlines)):
                 y2 = slot.y_offset + count
                 if lm:
+                    i = 0
                     lcont = j > 0
-                    rstrs = slot.window.mode.get_lmargin(w, y, x, ended, lcont)
+                    rstrs = w.mode.get_lmargin(w, y, x, ended, lcont)
                     for rstr in rstrs:
-                        rstr.draw(self.win, y2, 0)
+                        rstr.draw(self.win, y2, i)
+                        i += rstr.width(w)
+                i = lm
                 for rstr in rlines[j]:
-                    rstr.draw(self.win, y2, 0 + lm)
+                    rstr.draw(self.win, y2, i)
+                    i += rstr.width(w)
                 if rm:
+                    i = slot.width - rm
                     rcont = j < len(rlines) - 1
-                    rstrs = slot.window.mode.get_rmargin(w, y, x, ended, rcont)
+                    rstrs = w.mode.get_rmargin(w, y, x, ended, rcont)
                     for rstr in rstrs:
-                        rstr.draw(self.win, y2, slot.width - rm)
+                        rstr.draw(self.win, y2, i)
+                        i += rstr.width(w)
                 count += 1
                 if count >= slot.height:
                     break

render.py

@@ -30,15 +30,13 @@ class RenderString(object):
         self.y      = y
         self.x      = x
         self.attrs  = attrs
-    def draw(self, cwin, y, x, x2=None):
+    def width(self, w):
+        l = len(self.string)
+        #l += self.string.count('\t') * (w.mode.tabwidth - 1)
+        return l
+    def draw(self, cwin, y, x):
         try:
-            if x2:
+            s = self.string.encode('utf-8')
-                s = '%-*s' % (x2 - x, self.string)
+            cwin.addstr(self.y + y, x, s, self.attrs)
-            else:
-                s = self.string
-            s2 = s.encode('utf-8')
-            cwin.addstr(self.y + y, self.x + x, s2, self.attrs)
         except curses.error:
             raise
-            #v = (self.y, y, self.x, x, self.string, self.attrs, str(e))
-            #raise Exception, "cwin.addstr(%d + %d, %d + %d, %r, %r) failed:\n%s" % v