[External routines]

Pmode lib

MP4

dword _PointInBox(word X, word Y, word BoxULCornerX, word BoxULCornerY, word BoxLRCornerX, word BoxLRCornerY)

• Inputs:
• X - x coordinate of point in question
• Y - y coordinate of point in question
• BoxULCornerX - x coordinate of upper-left hand corner of box
• BoxULCornerY - y coordinate of upper-left hand corner of box
• BoxLRCornerX - x coordinate of lower_right hand corner of box
• BoxLRCornerY - y coordinate of lower_right hand corner of box
• Outputs: -
• Returns: 1 if BoxULCornerX <= X <= BoxLRCornerX and BoxULCornerY <= Y <= BoxLRCornerY; 0 otherwise
• Calls: -
• determines if the point (X, Y) is located in the box formed by the points (BoxULCornerX, BoxULCornerY) and (BoxLRCornerX, BoxLRCornerY)

void _ClearBuffer(dword *DestOff, word DestWidth, word DestHeight, dword Color)

• Inputs:
• DestOff - offset of image buffer in memory
• DestWidth - width of the buffer
• DestHeight - height of the buffer
• Color - color to clear with
• Outputs: color copied to buffer
• Returns: -
• Calls: -
• Clears pointed buffer by filling it with Color

void _CopyBuffer(dword *SrcOff, word SrcWidth, word SrcHeight, dword *DestOff, word DestWidth, word DestHeight, word X, word Y)

• Inputs:
• SrcOff - offset of source buffer
• SrcWidth - width of source buffer
• SrcHeight - height of source buffer
• DestOff - offset of destination buffer
• DestWidth - width of destination buffer
• DestHeight - height of destination buffer
• X - x coordinate of start point in destination buffer
• Y - y coordinate of start point in destination buffer
• Outputs: source buffer copied to destination buffer
• Returns: -
• Calls: -
• Copies the pointed source buffer to (X,Y) in the pointed destination buffer

void _ComposeBuffers(dword *SrcOff, word SrcWidth, word SrcHeight, dword *DestOff, word DestWidth, word DestHeight, word X, word Y)

• Inputs:
• SrcOff - offset of source buffer
• SrcWidth - width of source buffer
• SrcHeight - height of source buffer
• DestOff - offset of destination buffer
• DestWidth - width of destination buffer
• DestHeight - height of destination buffer
• X - x coordinate of start point in destination buffer
• Y - y coordinate of start point in destination buffer
• Outputs: source buffer alpha composed onto destination buffer
• Returns: -
• Calls: -
• Alpha composes source buffer onto destination buffer