From 10549ff7ae2dc99ef39f72bb6c2c43fcf7ac74ad Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop+git@gmail.com>
Date: Fri, 1 Apr 2011 23:49:09 -0400
Subject: [PATCH] initial attempt at panning, need to redraw

---
 SketchWidget.py | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/SketchWidget.py b/SketchWidget.py
index ccd7a13..3459852 100644
--- a/SketchWidget.py
+++ b/SketchWidget.py
@@ -14,6 +14,7 @@ class SketchWidget:
         self.view_center = (0, 0)
         self.view_width = 4.0
         self.size = (1, 1)
+        self.panning = False
 
         # Configuration parameters
         self.line_width = 0.8
@@ -120,6 +121,16 @@ class SketchWidget:
     def distToScreenDist(self, dist):
         return dist / self.view_width * self.size[0]
 
+    def screenPtToPt(self, pt):
+        return ((pt[0] - self.size[0]) / self.size[0] * self.view_width
+                    + self.view_center[0] / 2,
+                (pt[1] - self.size[1]) / self.size[1] *
+                    (self.view_width * self.size[1] / self.size[0])
+                        + self.view_center[1] / 2)
+
+    def screenDistToDist(self, dist):
+        return dist * self.size[0] / self.view_width
+
     def drawLine(self, shape, size):
         pt0 = self.ptToScreenPt(shape.getPt(0))
         pt1 = self.ptToScreenPt(shape.getPt(1))
@@ -189,14 +200,21 @@ class SketchWidget:
         glPopAttrib()
 
     def button_press_event(self, widget, event, data = None):
-        print 'clicked'
-        print 'button:', event.button
+        if event.button == 2:
+            self.panning = True
+            self.panning_start = (event.x, event.y)
 
     def button_release_event(self, widget, event, data = None):
-        print 'unclicked button', event.button
+        if event.button == 2:
+            self.panning = False
 
     def motion_event(self, widget, event, data = None):
-        print 'motion'
+        if self.panning:
+            start_pt = self.screenPtToPt(self.panning_start)
+            this_pt = self.screenPtToPt((event.x, event.y))
+            self.view_center = (self.view_center[0] + this_pt[0] - start_pt[0],
+                    self.view_center[1] + this_pt[1] - start_pt[1])
+            self.panning_start = (event.x, event.y)
 
     def scroll_event(self, widget, event, data = None):
         if event.direction == gtk.gdk.SCROLL_UP: