Indicate the just-exported origin and basis x and y vectors after

exporting our view to any file that doesn't have a canvas size (and
therefore doesn't get everything shifted to fit with the requested
margins around it in the canvas).

[git-p4: depot-paths = "//depot/solvespace/": change = 2107]

draw.cpp

@@ -771,6 +771,8 @@ nogrid:;
         glEnd();
     }
 
+    // An extra line, used to indicate the origin when rotating within the
+    // plane of the monitor.
     if(SS.extraLine.draw) {
         glLineWidth(1);
         glxLockColorTo(Style::Color(Style::DATUM));
@@ -780,6 +782,32 @@ nogrid:;
         glEnd();
     }
 
+    // A note to indicate the origin in the just-exported file.
+    if(SS.justExportedInfo.draw) {
+        glxColorRGB(Style::Color(Style::DATUM));
+        Vector p = SS.justExportedInfo.pt,
+               u = SS.justExportedInfo.u,
+               v = SS.justExportedInfo.v;
+
+        glLineWidth(1.5);
+        glBegin(GL_LINES);
+            glxVertex3v(p.Plus(u.WithMagnitude(-15/scale)));
+            glxVertex3v(p.Plus(u.WithMagnitude(30/scale)));
+            glxVertex3v(p.Plus(v.WithMagnitude(-15/scale)));
+            glxVertex3v(p.Plus(v.WithMagnitude(30/scale)));
+        glEnd();
+
+        glxWriteText("(x, y) = (0, 0) for file just exported",
+            DEFAULT_TEXT_HEIGHT,
+            p.Plus(u.ScaledBy(10/scale)).Plus(v.ScaledBy(10/scale)), 
+            u, v, NULL, NULL);
+        glxWriteText("press Esc to clear this message",
+            DEFAULT_TEXT_HEIGHT,
+            p.Plus(u.ScaledBy(40/scale)).Plus(
+                   v.ScaledBy(-(DEFAULT_TEXT_HEIGHT)/scale)), 
+            u, v, NULL, NULL);
+    }
+
     // And finally the toolbar.
     if(SS.showToolbar) {
         ToolbarDraw();

export.cpp

@@ -175,6 +175,17 @@ void SolveSpace::ExportViewOrWireframeTo(char *filename, bool wireframe) {
                                u, v, n, origin, SS.CameraTangent()*SS.GW.scale,
                                out);
         }
+
+        if(!out->HasCanvasSize()) {
+            // These file formats don't have a canvas size, so they just
+            // get exported in the raw coordinate system. So indicate what
+            // that was on-screen.
+            SS.justExportedInfo.draw = true;
+            SS.justExportedInfo.pt = origin;
+            SS.justExportedInfo.u = u;
+            SS.justExportedInfo.v = v;
+            InvalidateGraphics();
+        }
     }
 
     edges.Clear();

graphicswin.cpp

@@ -334,10 +334,12 @@ void GraphicsWindow::MenuView(int id) {
     switch(id) {
         case MNU_ZOOM_IN:
             SS.GW.scale *= 1.2;
+            SS.later.showTW = true;
             break;
 
         case MNU_ZOOM_OUT:
             SS.GW.scale /= 1.2;
+            SS.later.showTW = true;
             break;
 
         case MNU_ZOOM_TO_FIT:
@@ -626,6 +628,7 @@ void GraphicsWindow::MenuEdit(int id) {
             SS.GW.ClearSuper();
             HideTextEditControl();
             SS.nakedEdges.Clear();
+            SS.justExportedInfo.draw = false;
             break;
 
         case MNU_SELECT_ALL: {

solvespace.h

@@ -428,6 +428,7 @@ public:
     virtual void Triangle(STriangle *tr) = 0;
     virtual void StartFile(void) = 0;
     virtual void FinishAndCloseFile(void) = 0;
+    virtual bool HasCanvasSize(void) = 0;
 };
 class DxfFileWriter : public VectorFileWriter {
 public:
@@ -439,6 +440,7 @@ public:
     void Bezier(SBezier *sb);
     void StartFile(void);
     void FinishAndCloseFile(void);
+    bool HasCanvasSize(void) { return false; }
 };
 class EpsFileWriter : public VectorFileWriter {
 public:
@@ -453,6 +455,7 @@ public:
     void Bezier(SBezier *sb);
     void StartFile(void);
     void FinishAndCloseFile(void);
+    bool HasCanvasSize(void) { return true; }
 };
 class PdfFileWriter : public VectorFileWriter {
 public:
@@ -469,6 +472,7 @@ public:
     void Bezier(SBezier *sb);
     void StartFile(void);
     void FinishAndCloseFile(void);
+    bool HasCanvasSize(void) { return true; }
 };
 class SvgFileWriter : public VectorFileWriter {
 public:
@@ -483,6 +487,7 @@ public:
     void Bezier(SBezier *sb);
     void StartFile(void);
     void FinishAndCloseFile(void);
+    bool HasCanvasSize(void) { return true; }
 };
 class HpglFileWriter : public VectorFileWriter {
 public:
@@ -495,6 +500,7 @@ public:
     void Bezier(SBezier *sb);
     void StartFile(void);
     void FinishAndCloseFile(void);
+    bool HasCanvasSize(void) { return false; }
 };
 class Step2dFileWriter : public VectorFileWriter {
     StepFileWriter sfw;
@@ -506,6 +512,7 @@ class Step2dFileWriter : public VectorFileWriter {
     void Bezier(SBezier *sb);
     void StartFile(void);
     void FinishAndCloseFile(void);
+    bool HasCanvasSize(void) { return false; }
 };
 class GCodeFileWriter : public VectorFileWriter {
 public:
@@ -518,6 +525,7 @@ public:
     void Bezier(SBezier *sb);
     void StartFile(void);
     void FinishAndCloseFile(void);
+    bool HasCanvasSize(void) { return false; }
 };
 
 #ifdef LIBRARY
@@ -710,6 +718,10 @@ public:
         double      scale; // pixels per mm
         Vector      origin;
     } bgImage;
+    struct {
+        bool        draw;
+        Vector      pt, u, v;
+    } justExportedInfo;
 
     class Clipboard {
 public: