2 files changed, 36 insertions, 37 deletions

diff --git a/Drawer.cpp b/Drawer.cpp
index 5b6a6d5..e3fe6e6 100644
--- a/Drawer.cpp
+++ b/Drawer.cpp
@@ -86,54 +86,53 @@ void Drawer::updateViewport() {
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   
-  if(getWidth() != 0 && getHeight() != 0) {
-    glTranslatef(-1, 1, 0);
+  if(getWidth() != 0 && getHeight() != 0)
     glScalef(2.0f/getWidth(), -2.0f/getHeight(), 1);
-  }
   
   gdk_gl_drawable_gl_end(drawable);
 }
 
 void Drawer::updateScrolling() {
-  if(getImageWidth() < getWidth())
-    xTranslate = (getImageWidth()-getWidth())/2;
+  if(getImageWidth()*scale < getWidth())
+    xCenter = 0;
   else
-    xTranslate = gtk_adjustment_get_value(hAdjustment);
+    xCenter = gtk_adjustment_get_value(hAdjustment);
   
-  if(getImageHeight() < getHeight())
-    yTranslate = (getImageHeight()-getHeight())/2;
+  if(getImageHeight()*scale < getHeight())
+    yCenter = 0;
   else 
-    yTranslate = gtk_adjustment_get_value(vAdjustment);
+    yCenter = gtk_adjustment_get_value(vAdjustment);
   
   update();
 }
 
 void Drawer::updateScrollbars(float x, float y) {
   const gdouble imageWidth = getImageWidth(), imageHeight = getImageHeight();
-  const gdouble width = getWidth(), height = getHeight();
-  gdouble upper, pageSize, value;
+  const gdouble width = getWidth()/scale, height = getHeight()/scale;
+  gdouble lower, upper, pageSize, value;
+  
   
   gdk_window_freeze_updates(drawingArea->window);
   
-  g_object_get(G_OBJECT(hAdjustment), "upper", &upper, "page_size", &pageSize, NULL);
-  g_object_set(G_OBJECT(hAdjustment), "upper", imageWidth, "page_size", width, NULL);
+  g_object_get(G_OBJECT(hAdjustment), "lower", &lower, "upper", &upper, "page_size", &pageSize, NULL);
+  g_object_set(G_OBJECT(hAdjustment), "lower", (-imageWidth+width)/2, "upper", (imageWidth+width)/2, "page_size", width, NULL);
   gtk_adjustment_changed(hAdjustment);
   
-  if((pageSize > upper && width < imageWidth) || upper == 0)
-    value = (imageWidth-width)/2;
+  if((pageSize > (upper-lower) && width < imageWidth) || upper == lower)
+    value = 0;
   else
-    value = (gtk_adjustment_get_value(hAdjustment)+pageSize*x)/upper*imageWidth-width*x;
-  gtk_adjustment_set_value(hAdjustment, MAX(MIN(value, imageWidth-width), 0));
+    value = gtk_adjustment_get_value(hAdjustment) + (x-0.5)*pageSize*(pageSize/width-1);
+  gtk_adjustment_set_value(hAdjustment, MAX(MIN(value, imageWidth/2), -imageWidth/2));
   
-  g_object_get(G_OBJECT(vAdjustment), "upper", &upper, "page_size", &pageSize, NULL);
-  g_object_set(G_OBJECT(vAdjustment), "upper", imageHeight, "page_size", height, NULL);
+  g_object_get(G_OBJECT(vAdjustment), "lower", &lower, "upper", &upper, "page_size", &pageSize, NULL);
+  g_object_set(G_OBJECT(vAdjustment), "lower", (-imageHeight+height)/2, "upper", (imageHeight+height)/2, "page_size", height, NULL);
   gtk_adjustment_changed(vAdjustment);
   
-  if((pageSize > upper && height < imageHeight) || upper == 0)
-    value = (imageHeight-height)/2;
+  if((pageSize > upper && height < imageHeight) || upper == lower)
+    value = 0;
   else
-    value = (gtk_adjustment_get_value(vAdjustment)+pageSize*y)/upper*imageHeight-height*y;
-  gtk_adjustment_set_value(vAdjustment, MAX(MIN(value, imageHeight-height), 0));
+    value = gtk_adjustment_get_value(vAdjustment) + (y-0.5)*pageSize*(pageSize/height-1);
+  gtk_adjustment_set_value(vAdjustment, MAX(MIN(value, imageHeight/2), -imageHeight/2));
   
   gdk_window_thaw_updates(drawingArea->window);
   
@@ -161,8 +160,8 @@ void Drawer::render() {
   glMatrixMode(GL_MODELVIEW);
   glPushMatrix();
   
-  glTranslatef(getImageWidth()/2-xTranslate, getImageHeight()/2-yTranslate, 0);
   glScalef(scale, scale, 1);
+  glTranslatef(-xCenter, -yCenter, 0);
   
   renderer.render(window->getLevel(), rect, scale);
   
@@ -179,8 +178,8 @@ Drawer::Drawer(Window *window, GdkGLConfig *glconfig)
   this->window = window;
   zoomExp = 0;
   scale = 100;
-  xTranslate = 0;
-  yTranslate = 0;
+  xCenter = 0;
+  yCenter = 0;
   
   drawer = gtk_table_new(2, 2, FALSE);
   g_object_ref_sink(G_OBJECT(drawer));
@@ -225,13 +224,13 @@ void Drawer::zoom(int zoom, float x, float y) {
 }
 
 void Drawer::imageToView(Vertex *v) const {
-  v->setX(v->getX()*scale+getImageWidth()/2-xTranslate);
-  v->setY(v->getY()*scale+getImageHeight()/2-yTranslate);
+  v->setX((v->getX()-xCenter)*scale + getWidth()/2);
+  v->setY((v->getY()-yCenter)*scale + getHeight()/2);
 }
 
 void Drawer::viewToImage(Vertex *v) const {
-  v->setX((v->getX()-getImageWidth()/2+xTranslate)/scale);
-  v->setY((v->getY()-getImageHeight()/2+yTranslate)/scale);
+  v->setX((v->getX()-getWidth()/2)/scale+xCenter);
+  v->setY((v->getY()-getHeight()/2)/scale+yCenter);
 }
 
 float Drawer::getImageWidth() const {
@@ -244,7 +243,7 @@ float Drawer::getImageWidth() const {
     }
   }
   
-  return (max-min+10)*scale;
+  return (max-min+10);
 }
 
 float Drawer::getImageHeight() const {
@@ -257,5 +256,5 @@ float Drawer::getImageHeight() const {
     }
   }
   
-  return (max-min+10)*scale;
+  return (max-min+10);
 }
diff --git a/Drawer.h b/Drawer.h
index bfebe10..236c72a 100644
--- a/Drawer.h
+++ b/Drawer.h
@@ -21,7 +21,7 @@ class Drawer {
     Window *window;
     
     float scale;
-    float xTranslate, yTranslate;
+    float xCenter, yCenter;
     
     // prevent shallow copy
     Drawer(const Drawer &w);
@@ -59,12 +59,12 @@ class Drawer {
     float getImageWidth() const;
     float getImageHeight() const;
 
-    float getXTranslate() const {
-      return xTranslate;
+    float getXCenter() const {
+      return xCenter;
     }
     
-    float getYTranslate() const {
-      return yTranslate;
+    float getYCenter() const {
+      return yCenter;
     }
     
     float getScale() const {