* generic/tkObj.c (GetPixelsFromObjEx): [Bug 3431491]: Use a bit of

	type hackery to allow numbers to be interpreted as coordinates (most
	notably on a canvas) without reinterpreting via a string.

2 files changed, 52 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 59769c3..cd34352 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2011-11-01  Donal K. Fellows  <dkf@users.sf.net>
+
+	* generic/tkObj.c (GetPixelsFromObjEx): [Bug 3431491]: Use a bit of
+	type hackery to allow numbers to be interpreted as coordinates (most
+	notably on a canvas) without reinterpreting via a string.
+
 2011-10-26  Don Porter  <dgp@users.sourceforge.net>
 
 	* changes:	Updates for 8.5.11.
diff --git a/generic/tkObj.c b/generic/tkObj.c
index d973bd4..cb222cb 100644
--- a/generic/tkObj.c
+++ b/generic/tkObj.c
@@ -39,6 +39,19 @@ typedef struct PixelRep {
 #define GET_COMPLEXPIXEL(objPtr)			\
     ((PixelRep *) (objPtr)->internalRep.twoPtrValue.ptr2)
 
+/*
+ * One of these structures is created per thread to store thread-specific
+ * data. In this case, it is used to contain references to selected
+ * Tcl_ObjTypes that we can use as screen distances without conversion. The
+ * "dataKey" below is used to locate the ThreadSpecificData for the current
+ * thread.
+ */
+
+typedef struct ThreadSpecificData {
+    Tcl_ObjType *doubleTypePtr;
+    Tcl_ObjType *intTypePtr;
+} ThreadSpecificData;
+static Tcl_ThreadDataKey dataKey;
 
 /*
  * The following structure is the internal representation for mm objects.
@@ -157,6 +170,38 @@ GetPixelsFromObjEx(
 	1.0,	10.0,	25.4,	0.35278 /*25.4 / 72.0*/
     };
 
+    /*
+     * Special hacks where the type of the object is known to be something
+     * that is just numeric and cannot require distance conversion. This pokes
+     * holes in Tcl's abstractions, but they are just for optimization, not
+     * semantics.
+     */
+
+    if (objPtr->typePtr != &pixelObjType) {
+	ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
+		Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));
+
+	if (tsdPtr->doubleTypePtr == NULL) {
+	    tsdPtr->doubleTypePtr = Tcl_GetObjType("double");
+	    tsdPtr->intTypePtr = Tcl_GetObjType("int");
+	}
+
+	if (objPtr->typePtr == tsdPtr->doubleTypePtr) {
+	    (void) Tcl_GetDoubleFromObj(interp, objPtr, &d);
+	    if (dblPtr != NULL) {
+		*dblPtr = d;
+	    }
+	    *intPtr = (int) d;
+	    return TCL_OK;
+	} else if (objPtr->typePtr == tsdPtr->intTypePtr) {
+	    (void) Tcl_GetIntFromObj(interp, objPtr, intPtr);
+	    if (dblPtr) {
+		*dblPtr = (double) (*intPtr);
+	    }
+	    return TCL_OK;
+	}
+    }
+
  retry:
     if (objPtr->typePtr != &pixelObjType) {
 	result = SetPixelFromAny(interp, objPtr);
@@ -271,7 +316,7 @@ Tk_GetDoublePixelsFromObj(
     if (result != TCL_OK) {
 	return result;
     }
-    if (!SIMPLE_PIXELREP(objPtr)) {
+    if (objPtr->typePtr == &pixelObjType && !SIMPLE_PIXELREP(objPtr)) {
 	PixelRep *pixelPtr;
 	pixelPtr = GET_COMPLEXPIXEL(objPtr);
 	if (pixelPtr->units >= 0) {