Raster to vector conversion system and method therefor

A method of converting raster data in a memory plane to vector output, the raster data having a bit for each pixel in a display, a first state of each bit corresponding to an illuminated pixel and a second state of each bit corresponding to an unilluminated pixel, said method comprising the steps of:

• (a) copying the raster data in the memory plane into a working copy so that the working copy contains all of the X,Y bits of the memory plane,
• (b) starting at a single predetermined bit in the working copy,
• (c) sequentially selecting and scanning a bit in the working copy to sense the presence of the first state and the second state,
• (d) in response to the sensing of the second state for a given scanned bit in step (c), moving to a next sequential bit and repeating step (c),
• (e) in response to the sensing of the first state in step (c) identifying all vectors having bits in the first state which have beginning coordinates corresponding to the given scanned bit,
• (f) in response to the identification of all vectors having beginning coordinates corresponding to the coordinates of the given scanned bit, selecting one vector according to a predetermined priority scheme,
• (g) outputting the beginning coordinate and an ending coordinate of the selected vector,
• (h) changing all of the bits of the selected vector from the first state to the second state in the working copy,
• (i) identifying all vectors having bits in the first state having beginning coordinates corresponding to the ending coordinates of the selected vector in step (f), and
• (j) in response to the identification of any vector in step (i) , repeating steps (f) through (j) , in the event no vectors are identified in step (i) repeating steps (c) through (j) so as to select and scan the next sequential bit in the working copy until all bits are sequentially scanned.

A method of converting raster data in a memory plane to drive a vector plotter, the raster data having a bit for each pixel in a display, a first state of each bit corresponding to an illuminated pixel and a second state of each bit corresponding to an unilluminated pixel, said method comprising the steps of:

• (a) copying the raster data in the memory plane into a working copy so that the working copy contains all of the X,Y bits of the memory plane,
• (b) starting at a single predetermined bit in the working copy,
• (c) scanning an individual bit in the working copy to sense the presence of the first state and the second state,
• (d) in response to the sensing of the second state for a given scanned bit in step (c), identifying a next sequential bit in the working copy, moving to the next sequential bit, and repeating step (c),
• (e) in response to the sensing of the first state in step (c) identifying all vectors having beginning coordinates corresponding to the given scanned bit,
• (f) in response to the identification of all vectors in step (e), selecting one vector according to the following predetermined priority scheme:
• (i) selecting horizontal and vertical vectors over diagonal vectors,
• (ii) selecting the longest vector in response to the selection in step (i),
• (iii) in the event the vectors are of equal length in step (ii), selecting horizontal vectors over vertical vectors,
• (g) drawing the selected vector with the vector plotter,
• (h) changing all of the bits of the selected vector from the first state to the second state in the memory plane,
• (i) identifying all vectors having bits in the first state having beginning coordinates corresponding to the ending coordinates of the vector selected in step (f), and
• (j) in response to the identification of any vector in step (i), repeating steps (f) through (j);
• in response to the failure to identify any vectors in step (i), identifying the next sequential bit in the working copy and repeating steps (c) through (j).

A method of converting raster X,Y bits in a memory to vector output, a first state of each bit in the memory corresponding to a lit pixel and a second state of each bit corresponding to an unlit pixel, said method comprising the steps of:

• (a) selecting and scanning a bit in the memory according to a predetermined pattern in order to sense the presence of the first and second states as follows:
• (i) in response to the sensing of the second state for the scanned bit, moving to a next sequential bit in the predetermined pattern of scanning,
• (ii) in response to the sensing of the first state for the given scanned bit identifying all vectors having beginning coordinates corresponding to the X,Y coordinate of the given scanned bit,
• (b) in response to the identification of all vectors in step (a)(ii) having a beginning coordinate corresponding to the X,Y coordinate of the given scanned bit, selecting one vector according to a predetermined priority scheme,
• (c) outputting the beginning and ending X,Y coordinates of the selected vector,
• (d) changing all of the bits of the selected vector determined by step (b) from the first state to the second state in the memory,
• (e) identify all vectors having bits in the first state having beginning X,Y coordinates corresponding to the ending coordinate of the selected vector determined by step (b),
• (f) in the event no vectors are identified in step (e), returning to step (a) so as to select and scan the next sequential bit in the predetermined pattern, and
• (g) in response to the identification of all vectors in step (e), selecting one vector according to the predetermined priority scheme and repeating steps (c) through (g).

A method of converting raster X,Y bits in a memory to vector output, said method comprising the steps of:

• (a) selecting and scanning one bit in the memory according to a predetermined pattern in order to identify all vectors having beginning coordinates corresponding to the X,Y coordinate of the selected scanned bit,
• (b) in response to the identification of all vectors in step (a) having a beginning coordinate corresponding to the X,Y coordinate of the selected scanned bit, selecting one vector according to a predetermined priority scheme,
• (c) outputting the beginning X,Y coordinate and an ending X,Y coordinate of the selected vector,
• (d) erasing all of the bits of the selected vector determined by step (b) in the memory,
• (e) identifying all vectors having bits having beginning X,Y coordinates corresponding to the ending coordinate of the selected vector determined by step (b),
• (f) in the event no vectors are identified in step (e), returning to step (a) so as to select and scan one next sequential bit in the predetermined pattern,
• (g) in response to the identification of all vectors in step (e), selecting one vector according to the predetermined priority scheme repeating steps (c) through (g).

A system of converting raster bits in a raster memory plane to vector output in real time, a first state of each bit in the memory plane corresponding to an illuminated pixel and a second state of each bit corresponding to an unilluminated pixel, said system comprising:

• means connected to said raster memory plane for storing a copy of said raster bits so that said copy contains all of said bits in the memory plane,
• means connected to said storing means and to said vector output for sequentially scanning each copied bit individually in said storing means according to a predetermined pattern in order to sense the presence of said first and second states,
• when said second state for a given bit is sensed, said scanning means scanning a next bit in said predetermined pattern;
• when said first state for the given bit is sensed, said scanning means identifying all vectors in said storing means having beginning coordinates corresponding to the X,Y coordinate of the given scanned bit;
• when said scanning means identifies more than one vector, said scanning means selecting one vector according to a predetermined priority scheme, identifying all end-to-end contiguous vectors to said selected vector and outputting the beginning and ending X,Y coordinates of the selected vector and all end-to-end contiguous vectors;
• said scanning means changing all of the bits of the selected vector and all end-to-end contiguous vectors from the first state to the second state in said storing means.