[lmi-commits] [lmi] master 01be23a 103/156: Automatically squeeze table columns to make them fit if necessary

[Greg Chicares]

branch: master
commit 01be23a639e7aca8cebc96b5a4e36e22e4c0386b
Author: Vadim Zeitlin <address@hidden>
Commit: Vadim Zeitlin <address@hidden>

    Automatically squeeze table columns to make them fit if necessary
    
    Some tables in the illustrations are so wide that they overflow the page
    width if the default generous column margins (~1em) are used, however
    globally decreasing the margins for all tables doesn't seem desirable as
    they look better with bigger margins.
    
    Solve this problem by making the column margin dynamic and reducing it
    automatically if the columns don't fit. This results in optimally
    looking tables in all cases and saves time on tweaking the columns
    manually to make them fit.
---
 wx_table_generator.cpp | 49 ++++++++++++++++++++++++++++++++++++++++++-------
 wx_table_generator.hpp |  1 +
 2 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/wx_table_generator.cpp b/wx_table_generator.cpp
index 5720f5d..078c4be 100644
--- a/wx_table_generator.cpp
+++ b/wx_table_generator.cpp
@@ -53,6 +53,7 @@ wx_table_generator::wx_table_generator
     ,total_width_(total_width)
     ,char_height_(dc_.GetCharHeight())
     ,row_height_((4 * char_height_ + 2) / 3) // Arbitrarily use 1.333 line 
spacing.
+    ,column_margin_(dc_.GetTextExtent("M").x)
     ,has_column_widths_(false)
     ,max_header_lines_(1)
 {
@@ -110,8 +111,7 @@ void wx_table_generator::add_column
             {
             increase_to_if_smaller(width, 
dc_.GetMultiLineTextExtent(header).x);
 
-            // Add roughly 1 em margins on both sides.
-            width += dc_.GetTextExtent("MM").x;
+            width += 2*column_margin_;
             }
         }
 
@@ -173,6 +173,8 @@ void 
wx_table_generator::do_compute_column_widths_if_necessary()
         return;
         }
 
+    has_column_widths_ = true;
+
     int num_expand = 0;
     int total_fixed = 0;
 
@@ -195,7 +197,43 @@ void 
wx_table_generator::do_compute_column_widths_if_necessary()
 
     if(total_width_ < total_fixed)
         {
-        warning() << "Not enough space for all fixed columns." << LMI_FLUSH;
+        auto const overflow = total_fixed - total_width_;
+
+        // If we have only fixed columns, try to make them fit by decreasing
+        // the margins around them if this can help, assuming that we can
+        // reduce them by up to half if really needed.
+        if(!num_expand)
+            {
+            int const num_columns = columns_.size();
+            auto const overflow_per_column =
+                (overflow + num_columns - 1)/num_columns;
+            if(overflow_per_column <= column_margin_)
+                {
+                for(auto& i : columns_)
+                    {
+                    if(i.is_hidden())
+                        {
+                        continue;
+                        }
+
+                    i.width_ -= overflow_per_column;
+                    }
+
+                column_margin_ -= (overflow_per_column + 1)/2;
+
+                // We condensed the columns enough to make them fit, so no need
+                // for the warning and we don't have any expanding columns, so
+                // we're done.
+                return;
+                }
+            }
+
+        warning()
+            << "Not enough space for all fixed columns: "
+            << overflow
+            << " more pixels needed."
+            << LMI_FLUSH
+            ;
         return;
         }
 
@@ -217,8 +255,6 @@ void 
wx_table_generator::do_compute_column_widths_if_necessary()
                 }
             }
         }
-
-    has_column_widths_ = true;
 }
 
 void wx_table_generator::do_output_values
@@ -266,8 +302,7 @@ void wx_table_generator::do_output_values
                     }
                 else
                     {
-                    // Otherwise just offset it by ~1 em.
-                    x_text += dc_.GetTextExtent("M").x;
+                    x_text += column_margin_;
                     }
             }
 
diff --git a/wx_table_generator.hpp b/wx_table_generator.hpp
index a71717c..5e138ff 100644
--- a/wx_table_generator.hpp
+++ b/wx_table_generator.hpp
@@ -155,6 +155,7 @@ class wx_table_generator
     // These values could be recomputed, but cache them for performance.
     int const char_height_;
     int row_height_;
+    int column_margin_;
 
     struct column_info
     {