Deduplicate flex logic for rtl

Related to #1225.

weasyprint/layout/flex.py

@@ -495,7 +495,7 @@ def flex_layout(context, box, max_position_y, skip_stack, containing_block,
             not_collected_items = []
             for i, child in line:
                 align_self = child.style['align_self']
-                if (box.style['flex_direction'].startswith('row') and
+                if (axis == 'width' and
                         align_self == 'baseline' and
                         child.margin_top != 'auto' and
                         child.margin_bottom != 'auto'):
@@ -649,62 +649,39 @@ def flex_layout(context, box, max_position_y, skip_stack, containing_block,
                         child.margin_bottom = free_space
             free_space = 0
 
-        if (box.style['direction'] == 'rtl' and
-                box.style['flex_direction'].startswith('row')):
-            if justify_content == 'flex-end':
-                position_axis -= free_space
-            elif justify_content == 'center':
-                position_axis -= free_space / 2
-            elif justify_content == 'space-around':
-                position_axis -= free_space / len(line) / 2
-            elif justify_content == 'space-evenly':
-                position_axis -= free_space / (len(line) - 1)
+        if box.style['direction'] == 'rtl' and axis == 'width':
+            free_space *= -1
 
-            for i, child in line:
-                if axis == 'width':
-                    child.position_x = position_axis
-                    if justify_content == 'stretch':
-                        child.width -= free_space / len(line)
-                else:
-                    child.position_y = position_axis
-                position_axis -= (
-                    child.margin_width() if axis == 'width'
-                    else child.margin_height())
-                if justify_content == 'space-around':
-                    position_axis -= free_space / len(line)
-                elif justify_content == 'space-between':
-                    if len(line) > 1:
-                        position_axis -= free_space / (len(line) + 1)
-                elif justify_content == 'space-evenly':
-                    position_axis -= free_space / (len(line) - 1)
-        else:
-            if justify_content == 'flex-end':
-                position_axis += free_space
-            elif justify_content == 'center':
-                position_axis += free_space / 2
-            elif justify_content == 'space-around':
-                position_axis += free_space / len(line) / 2
+        if justify_content == 'flex-end':
+            position_axis += free_space
+        elif justify_content == 'center':
+            position_axis += free_space / 2
+        elif justify_content == 'space-around':
+            position_axis += free_space / len(line) / 2
+        elif justify_content == 'space-evenly':
+            position_axis += free_space / (len(line) + 1)
+
+        for i, child in line:
+            if axis == 'width':
+                child.position_x = position_axis
+                if justify_content == 'stretch':
+                    child.width += free_space / len(line)
+            else:
+                child.position_y = position_axis
+            margin_axis = (
+                child.margin_width() if axis == 'width'
+                else child.margin_height())
+            if box.style['direction'] == 'rtl' and axis == 'width':
+                margin_axis *= -1
+            position_axis += margin_axis
+            if justify_content == 'space-around':
+                position_axis += free_space / len(line)
+            elif justify_content == 'space-between':
+                if len(line) > 1:
+                    position_axis += free_space / (len(line) - 1)
             elif justify_content == 'space-evenly':
                 position_axis += free_space / (len(line) + 1)
 
-            for i, child in line:
-                if axis == 'width':
-                    child.position_x = position_axis
-                    if justify_content == 'stretch':
-                        child.width += free_space / len(line)
-                else:
-                    child.position_y = position_axis
-                position_axis += (
-                    child.margin_width() if axis == 'width'
-                    else child.margin_height())
-                if justify_content == 'space-around':
-                    position_axis += free_space / len(line)
-                elif justify_content == 'space-between':
-                    if len(line) > 1:
-                        position_axis += free_space / (len(line) - 1)
-                elif justify_content == 'space-evenly':
-                    position_axis += free_space / (len(line) + 1)
-
     # Step 13
     position_cross = (
         box.content_box_y() if cross == 'height'