[dasher] Added guidelines for ClickFilter, also controlled by BP_{DRAW, CURVE}_MOUSE_LINE

[Patrick Welche <pwelche src gnome org>]

commit 8eb0f3757b898dd62d364f4eed546ae468c92673
Author: Alan Lawrence <acl33 inf phy cam ac uk>
Date:   Wed Jan 6 21:55:04 2010 +0000

    Added guidelines for ClickFilter, also controlled by BP_{DRAW,CURVE}_MOUSE_LINE

 Src/DasherCore/ClickFilter.cpp |   41 +++++++++++++++++++++++++++++++++++++++-
 Src/DasherCore/ClickFilter.h   |    3 ++
 2 files changed, 43 insertions(+), 1 deletions(-)
---
diff --git a/Src/DasherCore/ClickFilter.cpp b/Src/DasherCore/ClickFilter.cpp
index 62230f2..c7eeb03 100644
--- a/Src/DasherCore/ClickFilter.cpp
+++ b/Src/DasherCore/ClickFilter.cpp
@@ -7,10 +7,49 @@ using namespace Dasher;
 
 static SModuleSettings sSettings[] = {
   {LP_MAXZOOM, T_LONG, 11, 400, 10, 1, _("Maximum Zoom")},
+  {BP_DRAW_MOUSE_LINE, T_BOOL, -1, -1, -1, -1, _("Draw guides on screen to show area into which a click will zoom")},
+  {BP_CURVE_MOUSE_LINE, T_BOOL, -1, -1, -1, -1, _("Curve lines to follow the non-linearity of the view transform")},
 };
 
 bool CClickFilter::DecorateView(CDasherView *pView) {
-  return false;
+  bool bChanged(false);
+  if (GetBoolParameter(BP_DRAW_MOUSE_LINE)) {
+    myint mouseX, mouseY;
+    pView->GetCoordinates(mouseX, mouseY);
+    //unfortunately we have to copy the limit set by DasherModel::ScheduleZoom here
+    // ....call for a refactor? but of some/what sort?
+    if (mouseX<2) mouseX=2;
+    if (m_iLastX != mouseX || m_iLastY != mouseY) {
+      bChanged = true;
+      m_iLastX = mouseX; m_iLastY = mouseY;
+    }
+    myint x[3], y[3];
+    x[0] = x[2] = 0;
+    x[1] = mouseX;
+    y[0] = mouseY - mouseX;
+    y[1] = mouseY;
+    y[2] = mouseY + mouseX;
+    if (GetBoolParameter(BP_CURVE_MOUSE_LINE)) {
+      pView->DasherSpaceLine(x[0], y[0], x[1], y[1], GetLongParameter(LP_LINE_WIDTH), 1);
+      pView->DasherSpaceLine(x[1], y[1], x[2], y[2], GetLongParameter(LP_LINE_WIDTH), 1);
+    } else {
+      //Note that the nonlinearity at edges of screen causes the lines to wobble close to the top/bottom:
+      // we draw lines _straight_ towards their targets on the Y-axis (calculated after applying nonlinearity),
+      // but truncated to the visible portion of the screen.
+      //A quick/approximate (but wrong!) solution, to make the lines stay at much the same angle, is
+      // to draw them to intersect min/max visible y only, as follows:
+        //if (y[0] < iDasherMinY) {
+        //  x[0] = mouseX - (mouseY - iDasherMinY);
+        //  y[0] = iDasherMinY;
+        //}
+        //if (y[2] > iDasherMaxY) {
+        //  x[2] = mouseX - (iDasherMaxY - mouseY);
+        //  y[2] = iDasherMaxY;
+        //}
+      pView->DasherPolyline(x, y, 3, GetLongParameter(LP_LINE_WIDTH), 1);
+    }
+  }
+  return bChanged;
 }
 
 bool CClickFilter::Timer(int Time, CDasherView *pDasherView, CDasherModel *pModel, Dasher::VECTOR_SYMBOL_PROB *pAdded, int *pNumDeleted, CExpansionPolicy **pol) {
diff --git a/Src/DasherCore/ClickFilter.h b/Src/DasherCore/ClickFilter.h
index 7898de6..029655a 100644
--- a/Src/DasherCore/ClickFilter.h
+++ b/Src/DasherCore/ClickFilter.h
@@ -17,6 +17,9 @@ class CClickFilter : public CInputFilter {
   virtual bool Timer(int Time, CDasherView *pDasherView, CDasherModel *pDasherModel, Dasher::VECTOR_SYMBOL_PROB *pAdded, int *pNumDeleted, CExpansionPolicy **pol);
   virtual void KeyDown(int iTime, int iId, CDasherView *pDasherView, CDasherModel *pModel, CUserLogBase *pUserLog, bool bPos, int iX, int iY);
   virtual bool GetSettings(SModuleSettings **pSettings, int *iCount);
+ private:
+  //for mouse lines
+  myint m_iLastX, m_iLastY;
 };
 }
 /// @}