Index: trunk/src/obj_common.c
===================================================================
--- trunk/src/obj_common.c	(revision 19572)
+++ trunk/src/obj_common.c	(revision 19573)
@@ -226,3 +226,86 @@
 			return 0;
 	}
 }
+
+static void mmult(pcb_xform_mx_t dst, const pcb_xform_mx_t src)
+{
+	pcb_xform_mx_t tmp;
+
+	tmp[0] = dst[0] * src[0] + dst[1] * src[3] + dst[2] * src[6];
+	tmp[1] = dst[0] * src[1] + dst[1] * src[4] + dst[2] * src[7];
+	tmp[2] = dst[0] * src[2] + dst[1] * src[5] + dst[2] * src[8];
+
+	tmp[3] = dst[3] * src[0] + dst[4] * src[3] + dst[5] * src[6];
+	tmp[4] = dst[3] * src[1] + dst[4] * src[4] + dst[5] * src[7];
+	tmp[5] = dst[3] * src[2] + dst[4] * src[5] + dst[5] * src[8];
+
+	tmp[6] = dst[6] * src[0] + dst[7] * src[3] + dst[8] * src[6];
+	tmp[7] = dst[6] * src[1] + dst[7] * src[4] + dst[8] * src[7];
+	tmp[8] = dst[6] * src[2] + dst[7] * src[5] + dst[8] * src[8];
+
+	memcpy(dst, tmp, sizeof(tmp));
+}
+
+void pcb_xform_mx_rotate(pcb_xform_mx_t mx, double deg)
+{
+	pcb_xform_mx_t tr;
+
+	deg /= PCB_RAD_TO_DEG;
+
+	tr[0] = cos(deg);
+	tr[1] = sin(deg);
+	tr[2] = 0;
+
+	tr[3] = -sin(deg);
+	tr[4] = cos(deg);
+	tr[5] = 0;
+
+	tr[6] = 0;
+	tr[7] = 0;
+	tr[8] = 1;
+
+	mmult(mx, tr);
+}
+
+void pcb_xform_mx_translate(pcb_xform_mx_t mx, double xt, double yt)
+{
+	pcb_xform_mx_t tr;
+
+	tr[0] = 1;
+	tr[1] = 0;
+	tr[2] = xt;
+
+	tr[3] = 0;
+	tr[4] = 1;
+	tr[5] = yt;
+
+	tr[6] = 0;
+	tr[7] = 0;
+	tr[8] = 1;
+
+	mmult(mx, tr);
+}
+
+void pcb_xform_mx_scale(pcb_xform_mx_t mx, double sx, double sy)
+{
+	pcb_xform_mx_t tr;
+
+	tr[0] = sx;
+	tr[1] = 0;
+	tr[2] = 0;
+
+	tr[3] = 0;
+	tr[4] = sy;
+	tr[5] = 0;
+
+	tr[6] = 0;
+	tr[7] = 0;
+	tr[8] = 1;
+
+	mmult(mx, tr);
+}
+
+void pcb_xform_mx_mirrorx(pcb_xform_mx_t mx)
+{
+	pcb_xform_mx_scale(mx, 0, -1);
+}
Index: trunk/src/obj_common.h
===================================================================
--- trunk/src/obj_common.h	(revision 19572)
+++ trunk/src/obj_common.h	(revision 19573)
@@ -92,6 +92,9 @@
 	pcb_coord_t X2, Y2;     /* and lower right corner */
 };
 
+typedef double pcb_xform_mx_t[9];
+#define PCB_XFORM_MX_IDENT {1,0,0,   0,1,0,   0,0,1}
+
 typedef struct pcb_xform_s {   /* generic object transformation */
 	pcb_coord_t bloat;   /* if non-zero, bloat (positive) or shrink (negative) by this value */
 } pcb_xform_t;
@@ -106,6 +109,15 @@
 	} while(0)
 #define pcb_xform_is_nop(src) ((src)->bloat == 0)
 
+/* Standard 2d matrix transformation using mx as pcb_xform_mx_t */
+#define pcb_xform_x(mx, x_in, y_in) ((double)(x_in) * mx[0] + (double)(y_in) * mx[1] + mx[2])
+#define pcb_xform_y(mx, x_in, y_in) ((double)(x_in) * mx[3] + (double)(y_in) * mx[4] + mx[5])
+
+void pcb_xform_mx_rotate(pcb_xform_mx_t mx, double deg);
+void pcb_xform_mx_translate(pcb_xform_mx_t mx, double xt, double yt);
+void pcb_xform_mx_scale(pcb_xform_mx_t mx, double st, double sy);
+void pcb_xform_mx_mirrorx(pcb_xform_mx_t mx); /* mirror over the x axis (flip y coords) */
+
 /* Return the user readable name of an object type in a string; never NULL */
 const char *pcb_obj_type_name(pcb_objtype_t type);