Image processing apparatus and external storage unit

An external storage unit in combination with an image processing apparatus for displaying an image on a display according to the color data for each dot, said external storage unit comprising:

• character data storing means for storing character data of moving picture characters and still picture characters;
• and
• color arithmetic program storing means for storing a color arithmetic program for executing a color arithmetic operation, said color arithmetic program including command data for specifying an addition operation or a subtraction operation;
• said image processing apparatus including first color data generating means for generating first color data of a first image in response to said character data read from said external storage unit;
• second color data generating means for generating second color data of a second image in response to said character data read from said external storage unit;
• data outputting means for receiving one of said first color data and said second color data and for outputting said one of said first color data and said second color data unchanged when said command data specifies said addition operation and for outputting data that is obtained by logically inverting said one of said first color data and said second color data when said command data specifies said subtraction operation;
• adding means for adding data outputted from said data outputting means to the other of said first color data and said second color data to output result color data in response to said color arithmetic program read from said external storage unit;
• data shift command generating means for generating a data shift command;
• data shift means for receiving said result data from said adding means and for outputting shifted color data that is obtained by 1-bit shifting said result color data in response to said data shift command or outputting said result color data as it is when no data shift command is outputted from said data shift command generating means, and
• video signal generating means for converting said shifted color data or said result color data outputted from said data shift means into a video signal.

An image processing apparatus for displaying an image on a display according to color data of each dot, comprising:

• image data generating means for generating color data of a plurality of images;
• first color data generating means for selecting a first color data of an arbitrary first image out of said plurality of images generated by said image data generating means;
• second color data generating means for selecting a second color data of an arbitrary second image out of said plurality of images generated by said image data generating means;
• command generating means for generating an addition command or a subtraction command;
• data outputting means for receiving one of said first color data and said second color data and for outputting said one of said first color data and said second color data unchanged in response to said addition command and for outputting data that is obtained by logically inverting said one of said first color data and said second color data in response to said subtraction command;
• adding means for adding data outputted from said data outputting means to the other of said first color data and said second color data to output result color data;
• video signal generating means for converting the result color data from said adding means into a video signal to apply said video signal to said display;
• data shift command generating means for generating a data shift command;
• and
• data shift means for receiving said result data from said adding means and for outputting shifted color data that is obtained by 1-bit shifting said result color data in response to said data shift command or outputting said result color data as it is when no data shift command is outputted from said data shift command generating means, wherein
• said video signal generating means converts said shifted color data or said result color data outputted from said data shift means into the video signal.

An image processing apparatus for displaying an image on a display according to color data of each dot, comprising:

• a first color generator for generating first color data of a first image;
• a second color generator for generating second color data of a second image;
• a range generator for generating color window range data specifying a color window range within a screen of said display;
• an arithmetic circuit for performing an arithmetic operation on said first color data and said second color data only within the range specified by said color window range data to output result color data;
• a data shift command generator for generating a data shift command;
• a data shift circuit for receiving said result color data from said arithmetic circuit and for outputting shifted color data that is obtained by 1-bit shifting said result color data in response to said data shift command or outputting said result color data as it is when no data shift command is outputted from said data shift command generator, and
• a video signal generator for converting said shifted color data or said result color data outputted from said data shift circuit into a video signal.

An external storage unit in combination with an image processing apparatus for displaying an image on a display according to the color data of each dot, said external storage unit comprising:

• character data storing means for storing character data of moving picture characters and still picture characters;
• and
• color arithmetic program storing means for storing a color arithmetic program for executing a color arithmetic operation, said color arithmetic program including color window range data for specifying a color window range within a screen of said display;
• wherein said image processing means comprises
• means for generating first color data of a first image on the basis of character data read from said external storage unit;
• means for generating second color data of a second image on the basis of character data read from said external storage unit;
• means for performing an arithmetic operation on said first color data and said second color data only within the range specified by said color window range data on the basis of said color arithmetic program read from said external storage unit to output result color data;
• data shift command generating means for generating a data shift command;
• and
• data shift means for receiving said result color data from said means for performing an arithmetic operation and for outputting shifted color data that is obtained by 1-bit shifting said result color data in response to said data shift command or outputting said result color data as it is when no data shift command is outputted from said data shift command generating means, and
• video signal generating means for converting said shifted color data or said result color data outputted from said data shift means into a video signal.