A word processor capable of creating a formula during a document editing process by automatically setting a range of a formula in a document being edited with an instrument of a formula process start command and allowing a switching operation between the document editing process and the formula creating process to be easily made. This allows the formula to be edited on a block basis, thereby facilitating the editing operation such as modification, addition, or deletion of the formula in accordance with any editing of character trains or symbols inside and outside the formula in a well-balanced manner. The word processor is also capable of automatically defining the position, size, and form of a symbol in accordance with the length and form of an object to which the symbol is to be added, so that the position, size, and form of the symbol can be automatically accommodated in accordance with any change in the object to which the symbol is to be added without bothering an operator. The word processor is further capable of not only adding a symbol to an already input text, but also inputting paired symbols which are mutually spaced apart such as a pair of parentheses with a single input operation.
If an unnecessary sentence is included in data tabulated at a display, a head address is prepared in a memory region for storing a new data group. A counter m indicating a function and a counter n indicating a data number corresponding to the function are initialized. A determination whether or not the data (Y(m)) is necessary is made for every function (X(m, n)), and the only necessary data is stored in the memory. This operation is performed to check four functions and 100 pieces of data for each of the four functions. When the operation is completed, the resultant data is stored as a set of data in the memory.
An image processing system receives different types of image data with different number of bits per pixel, stores the image data into a memory, and applies given image processing steps to the image data stored therein. A control device is included in the image processing system. The control device determines the positions of pixels to be image processed, the number of pixels of one line, and the number of lines. For each line a least common multiple (LCM) of the number of bits of the pixel (B.sub.m) and the number of bits per access of the image data used in the image processing system (B.sub.0) is calculated, and the control device executes preset image processing programs under the determined conditions.
An apparatus for editing documents input from an input device, capable of reducing a process time of renewing the documents to be displayed on a display device and capable of increasing a displaying speed of the renewed documents during an editing process includes a document storing unit for storing document data, a text-layout information storing unit for storing text-layout information separately in accordance with a preceding time and a succeeding time with respect to an editing operation, the text-layout information indicating positions of the document data on the display device at a time when the document data are displaying, a display image storing unit for storing image data, the image data being used for displaying the document data stored in the document storing unit on the display device in accordance with the text-layout information in the preceding time stored in the text-layout information storing unit, an editing unit for producing the text-layout information in the succeeding time from the text-layout information in the preceding time stored in the text-layout information storing unit and the document data stored in the storing unit in accordance with an indication input from the input device, and a processing unit for renewing the image data stored in the display image storing unit in accordance with a process of redisplaying characters and a process of transmitting the image data.
