From ac10c408e3f93558eab20dc5c3533b692f4166a7 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Thu, 6 Jun 2013 05:19:52 -0500
Subject: [PATCH] optimize rendering even more.

---
 lib/widget.js | 38 +++++++++++++++++++++++++++++++-------
 1 file changed, 31 insertions(+), 7 deletions(-)

diff --git a/lib/widget.js b/lib/widget.js
index b0bdec7..b15da95 100644
--- a/lib/widget.js
+++ b/lib/widget.js
@@ -197,10 +197,16 @@ Screen.prototype.alloc = function() {
     this.lines[y] = [];
     for (x = 0; x < this.cols; x++) {
       this.lines[y][x] = [this.dattr, ' '];
-      //this.lines[y][x].dirty = true;
     }
     this.lines[y].dirty = true;
   }
+  this.olines = [];
+  for (y = 0; y < this.rows; y++) {
+    this.olines[y] = [];
+    for (x = 0; x < this.cols; x++) {
+      this.olines[y][x] = [];
+    }
+  }
 };
 
 Screen.prototype.render = function() {
@@ -222,11 +228,18 @@ Screen.prototype.draw = function(start, end) {
     , bgColor
     , flags;
 
+  var lx = -1
+    , ly = -1
+    , o;
+
   this.program.saveCursor();
+  //this.program.write('\x1b[1;1H');
 
   for (y = start; y <= end; y++) {
     line = this.lines[y];
+    o = this.olines[y];
 
+    // TODO: Possibly get rid of .dirty altogether.
     if (!line.dirty) continue;
     line.dirty = false;
 
@@ -237,6 +250,21 @@ Screen.prototype.draw = function(start, end) {
       data = line[x][0];
       ch = line[x][1];
 
+      if (data === o[x][0] && ch === o[x][1]) {
+        if (lx === -1) {
+          lx = x;
+          ly = y;
+        }
+        continue;
+      } else if (lx !== -1) {
+        out += y === ly
+          ? '\x1b[' + (x - lx) + 'C'
+          : '\x1b[' + (y + 1) + ';' + (x + 1) + 'H';
+        lx = -1, ly = -1;
+      }
+      o[x][0] = data;
+      o[x][1] = ch;
+
       if (data !== attr) {
         if (attr !== this.dattr) {
           out += '\x1b[m';
@@ -315,7 +343,8 @@ Screen.prototype.draw = function(start, end) {
 
     //this.program.move(y + 1, 1);
     //this.program.write(out);
-    this.program.write('\x1b[' + (y + 1) + ';1H' + out);
+    if (out) this.program.write('\x1b[' + (y + 1) + ';1H' + out);
+    //if (out) this.program.write(lx !== -1 ? out : '\x1b[' + (y + 1) + ';1H' + out);
   }
 
   this.program.restoreCursor();
@@ -651,7 +680,6 @@ Box.prototype.render = function() {
       //      lines[yi][xi][0] = attr;
       //      lines[yi][xi][1] = ch;
       //      lines[yi].dirty = true;
-      //      //lines[yi][xi].dirty = true;
       //    }
       //  }
       //}
@@ -660,7 +688,6 @@ Box.prototype.render = function() {
         lines[yi][xi][0] = attr;
         lines[yi][xi][1] = ch;
         lines[yi].dirty = true;
-        //lines[yi][xi].dirty = true;
       }
     }
   }
@@ -764,7 +791,6 @@ Text.prototype.render = function() {
       //      lines[yi][xi][0] = attr;
       //      lines[yi][xi][1] = ch;
       //      lines[yi].dirty = true;
-      //      //lines[yi][xi].dirty = true;
       //    }
       //  }
       //}
@@ -773,7 +799,6 @@ Text.prototype.render = function() {
         lines[yi][xi][0] = attr;
         lines[yi][xi][1] = ch;
         lines[yi].dirty = true;
-        //lines[yi][xi].dirty = true;
       }
     }
   }
@@ -1086,7 +1111,6 @@ ProgressBar.prototype.render = function() {
         lines[y][x][0] = attr;
         lines[y][x][1] = ch;
         lines[y].dirty = true;
-        //lines[y][x].dirty = true;
       }
     }
   }