Fix setNames intruding into dividers when back_offset_height given negative value (#262)

* consolidate code for drawing backsides
* drawSetNames: no need to calculate xPos / yPos per card
* Account for back_offset when calculating set name placement

Without this, if you had a negative back_offset_height (or
positive back_offset), it was possible to print set names that
would intrude onto the divider area on the backs

* draw setNames along side (left or bottom) with more space

This both provides more cushion, and makes it less likely that
location will change between front + back (due to back_offset_height)

src/domdiv/draw.py

@@ -1561,7 +1561,7 @@ class DividerDrawer(object):
         # retore the canvas state to the way we found it
         self.canvas.restoreState()
 
-    def drawSetNames(self, pageItems):
+    def drawSetNames(self, pageItems, backside=False):
         # print sets for this page
         self.canvas.saveState()
 
@@ -1573,51 +1573,49 @@ class DividerDrawer(object):
             font = pdfmetrics.getFont(fontname)
             fontHeightRelative = (font.face.ascent + abs(font.face.descent)) / 1000.0
 
-            canFit = False
-
             layouts = [
                 {
                     "rotation": 0,
                     "minMarginHeight": self.options.minVerticalMargin,
-                    "totalMarginHeight": self.options.verticalMargin,
+                    "totalMarginHeight": self.options.verticalMargin
+                    + (self.options.back_offset_height if backside else 0),
                     "width": self.options.paperwidth,
                 },
                 {
                     "rotation": 90,
                     "minMarginHeight": self.options.minHorizontalMargin,
-                    "totalMarginHeight": self.options.horizontalMargin,
+                    "totalMarginHeight": self.options.horizontalMargin
+                    + (-self.options.back_offset if backside else 0),
                     "width": self.options.paperheight,
                 },
             ]
 
-            for layout in layouts:
+            # Pick whether to print setnames horizontally along bottom
+            # (i=0) or vertically along left (i=1).  We pick whichever has more
+            # space.
+            fontsize = 0
+            maxAvailableMargin = 0
+            layoutIndex = -1
+            for i, layout in enumerate(layouts):
                 availableMargin = (
                     layout["totalMarginHeight"] - layout["minMarginHeight"]
                 )
+                if availableMargin > maxAvailableMargin:
+                    maxAvailableMargin = availableMargin
                     fontsize = availableMargin / fontHeightRelative
                     fontsize = min(maxFontsize, fontsize)
-                if fontsize >= minFontsize:
+                    layoutIndex = i
-                    canFit = True
-                    break
 
-            if not canFit:
+            if fontsize < minFontsize:
                 import warnings
 
                 warnings.warn("Not enough space to display set names")
                 return
 
+            layout = layouts[layoutIndex]
+
             self.canvas.setFont(fontname, fontsize)
 
-            xPos = layout["width"] / 2
-            # Place at the very edge of the margin
-            yPos = layout["minMarginHeight"]
-
-            sets = []
-            for item in pageItems:
-                setTitle = item.card.cardset.title()
-                if setTitle not in sets:
-                    sets.append(setTitle)
-
             # Centered on page
             xPos = layout["width"] / 2
             # Place at the very edge of the margin
@@ -1627,6 +1625,12 @@ class DividerDrawer(object):
                 self.canvas.rotate(layout["rotation"])
                 yPos = -yPos
 
+            sets = []
+            for item in pageItems:
+                setTitle = item.card.cardset.title()
+                if setTitle not in sets:
+                    sets.append(setTitle)
+
             self.canvas.drawCentredString(xPos, yPos, "/".join(sets))
         finally:
             self.canvas.restoreState()
@@ -1975,39 +1979,35 @@ class DividerDrawer(object):
         for pageNum, pageInfo in enumerate(self.pages):
             hMargin, vMargin, page = pageInfo
 
-            # Front page footer
+            drawFooter = not self.options.no_page_footer and (
-            if not self.options.no_page_footer and (
                 not self.options.tabs_only and self.options.order != "global"
-            ):
-                self.drawSetNames(page)
-
-            # Front page
-            for item in page:
-                # print the dividor
-                self.drawDivider(
-                    item, isBack=False, horizontalMargin=hMargin, verticalMargin=vMargin
             )
-            self.canvas.showPage()
+
-            if pageNum + 1 == self.options.num_pages:
-                break
             if (
                 self.options.tabs_only
                 or self.options.text_back == "none"
                 or self.options.wrapper
             ):
                 # Don't print the sheets with the back of the dividers
-                continue
+                backSides = [False]
+            else:
+                backSides = [False, True]
 
-            # back page footer
+            for isBack in backSides:
-            if not self.options.no_page_footer and self.options.order != "global":
+                # Page footer
-                self.drawSetNames(page)
+                if drawFooter:
+                    self.drawSetNames(page, isBack)
 
-            # Back page
+                # Page
                 for item in page:
                     # print the dividor
                     self.drawDivider(
-                    item, isBack=True, horizontalMargin=hMargin, verticalMargin=vMargin
+                        item,
+                        isBack=isBack,
+                        horizontalMargin=hMargin,
+                        verticalMargin=vMargin,
                     )
                 self.canvas.showPage()
+
             if pageNum + 1 == self.options.num_pages:
                 break