Speed enhancement of canvas
Despite the use of Tcl_Obj every coordinate of a canvas item
is converted to a string and then to a double value plus
unit.
This patch (6 new lines) speeds up the common case, where the
coordiante is already a double value without unit. In my
application (Linux 2.2.17) I get a speed up by a factor of 2!
--- tkObj.orig.c Tue Nov 7 20:35:43 2000
+++ tkObj.c Wed Nov 8 19:44:41 2000
@@ -501,48 +501,54 @@
int units;
MMRep *mmPtr;
- string = Tcl_GetStringFromObj(objPtr, NULL);
-
- d = strtod(string, &rest);
- if (rest == string) {
- /*
- * Must copy string before resetting the result in case a caller
- * is trying to convert the interpreter's result to mms.
- */
-
- error:
- Tcl_AppendResult(interp, "bad screen distance \"", string,
- "\"", (char *) NULL);
- return TCL_ERROR;
+ if( objPtr->typePtr == &tclDoubleType ) {
+ /* optimize for speed reasons */
+ Tcl_GetDoubleFromObj( interp, objPtr, &d );
+ units = -1;
+ } else {
+ string = Tcl_GetStringFromObj(objPtr, NULL);
+
+ d = strtod(string, &rest);
+ if (rest == string) {
+ /*
+ * Must copy string before resetting the result in case a caller
+ * is trying to convert the interpreter's result to mms.
+ */
+
+ error:
+ Tcl_AppendResult(interp, "bad screen distance \"", string,
+ "\"", (char *) NULL);
+ return TCL_ERROR;
+ }
+ while ((*rest != '\0') && isspace(UCHAR(*rest))) {
+ rest++;
+ }
+ switch (*rest) {
+ case '\0':
+ units = -1;
+ break;
+
+ case 'c':
+ units = 0;
+ break;
+
+ case 'i':
+ units = 1;
+ break;
+
+ case 'm':
+ units = 2;
+ break;
+
+ case 'p':
+ units = 3;
+ break;
+
+ default:
+ goto error;
+ }
}
- while ((*rest != '\0') && isspace(UCHAR(*rest))) {
- rest++;
- }
- switch (*rest) {
- case '\0':
- units = -1;
- break;
-
- case 'c':
- units = 0;
- break;
-
- case 'i':
- units = 1;
- break;
-
- case 'm':
- units = 2;
- break;
-
- case 'p':
- units = 3;
- break;
-
- default:
- goto error;
- }
-
+
/*
* Free the old internalRep before setting the new one.
*/
