Methods and apparatus for tracking the active window of a host computer in a remote computer display window

A method for presenting in a display window a portion of a computer display screen image, the portion being defined by a moveable viewport rectangle, the method comprising the steps of:

• receiving a new active window message specifying an active window rectangle;
• determining whether the moveable viewport rectangle intersects the active window rectangle;
• and
• if the determining step determines that the moveable viewport rectangle does not intersect the active window rectangle, moving the moveable viewport rectangle to intersect the active window rectangle, wherein the step of moving the moveable viewport rectangle to intersect the active window rectangle comprises the steps of:
• if a moveable viewport rectangle width is less than an active window rectangle width, aligning a moveable viewport rectangle new left edge to an active window rectangle left edge;
• if a moveable viewport rectangle height is less than an active window rectangle height, aligning a moveable viewport rectangle new top edge to an active window rectangle top edge;
• if the moveable viewport rectangle width is not less than an active window rectangle width, horizontally positioning the moveable viewport rectangle new left edge such that the active window rectangle will be horizontally centered within the moveable viewport rectangle;
• and
• if the moveable viewport rectangle height is not less than an active window rectangle height, vertically positioning the moveable viewport rectangle new top edge such that the active window rectangle will be vertically centered within the moveable viewport rectangle.

A computer readable storage medium comprising:

• computer readable program code embodied on said computer readable storage medium, said computer readable program code for programming a computer to perform a method for presenting in a display window of a remote computer a portion of a host computer display screen image, the portion being defined by a moveable viewport rectangle, the method comprising the steps of:
• generating within said remote computer a copy of said host computer display screen image;
• receiving from said host computer a new active window message specifying an active window rectangle, wherein said new active window message corresponds to a portion of said copy of said host computer display screen image;
• determining whether the moveable viewport rectangle intersects the active window rectangle;
• and
• if the determining step determines that the moveable viewport rectangle does not intersect the active window rectangle, moving the moveable viewport rectangle to intersect the active window rectangle.

A computer readable storage medium comprising:

• computer readable program code embodied on said computer readable storage medium, said computer readable program code for programming a computer to perform a method for presenting in a display window a portion of a computer display screen image, the portion being defined by a moveable viewport rectangle, the method comprising the steps of:
• receiving a new active window message specifying an active window rectangle;
• determining whether the moveable viewport rectangle intersects the active window rectangle;
• and
• if the determining step determines that the moveable viewport rectangle does not intersect the active window rectangle, moving the moveable viewport rectangle to intersect the active window rectangle, wherein the step of moving the moveable viewport rectangle to intersect the active window rectangle comprises the steps of:
• if a moveable viewport rectangle width is less than an active window rectangle width, aligning a moveable viewport rectangle new left edge to an active window rectangle left edge;
• if a moveable viewport rectangle height is less than an active window rectangle height, aligning a moveable viewport rectangle new top edge to an active window rectangle top edge;
• if the moveable viewport rectangle width is not less than an active window rectangle width, horizontally positioning the moveable viewport rectangle new left edge such that the active window rectangle will be horizontally centered within the moveable viewport rectangle;
• and
• if the moveable viewport rectangle height is not less than an active window rectangle height, vertically positioning the moveable viewport rectangle new top edge such that the active window rectangle will be vertically centered within the moveable viewport rectangle.

A remote computer system comprising:

• a remote computer display for displaying a remote computer screen image;
• a remote computer display bitmap, coupled to the remote computer display, for storing a digital representation of the remote computer screen image;
• and
• a remote application, coupled to the remote computer display bitmap, for writing a portion of the remote computer display bitmap corresponding to a display window, the remote application including:
• a copy of a host computer display bitmap for storing a digital representation of a host computer screen image;
• and
• a remote new active window message handling means coupled to the copy of the host computer display bitmap for receiving a new active window message specifying an active window rectangle, for moving a moveable viewport rectangle so as to intersect the active window rectangle, and for writing the portion of the remote computer display bitmap corresponding to the display window with a portion of the copy of the host computer display bitmap corresponding to the moveable viewport rectangle, wherein the remote new active window message handling means is operable to:
• if a moveable viewport rectangle width is less than an active window rectangle width, aligning a moveable viewport rectangle new left edge to an active window rectangle left edge;
• if a moveable viewport rectangle height is less than an active window rectangle height, aligning a moveable viewport rectangle new top edge to an active window rectangle top edge;
• if the moveable viewport rectangle width is not less than an active window rectangle width, horizontally positioning the moveable viewport rectangle new left edge such that the active window rectangle will be horizontally centered within the moveable viewport rectangle;
• if the moveable viewport rectangle height is not less than an active window rectangle height, vertically positioning the moveable viewport rectangle new top edge such that the active window rectangle will be vertically centered within the moveable viewport rectangle;
• if the moveable viewport rectangle new left edge is left of a computer display left edge, aligning the moveable viewport rectangle new left edge to the computer display left edge;
• if a moveable viewport rectangle new right edge is left of a computer display right edge, aligning the moveable viewport rectangle new right edge to the computer display right edge;
• if the moveable viewport rectangle new top edge is above a computer display top edge, aligning the moveable viewport rectangle new top edge to the computer display top edge;
• and
• if a moveable viewport rectangle new bottom edge is below a computer display bottom edge, aligning the moveable viewport rectangle new bottom edge to the computer display bottom edge.