bitmap(X) 19 June 1992 bitmap(X) Name bitmap, bmtoa, atobm - bitmap editor and converter utilities for X Syntax bitmap [-options...] filename WIDTHxHEIGHT bmtoa [-chars...] [filename] atobm [chars cc] [-name variable] [-xhot number] [-yhot number] [filename] Description The bitmap program is a rudimentary tool for creating or editing rec- tangular images made up of 1's and 0's. Bitmaps are used in X for defin- ing clipping regions, cursor shapes, icon shapes, and tile and stipple patterns. The bmtoa and atobm filters convert bitmap files (FILE FORMAT) to and from ASCII strings. They are most commonly used to quickly print out bitmaps and to generate versions for including in text. Usage bitmap displays a grid in which each square represents a single bit in the picture being edited. Squares can be set, cleared, or inverted directly with the buttons on the pointer and a menu of higher level operations such as draw line and fill circle is provided to the side of the grid. Actual size versions of the bitmap as it would appear normally and inverted appear below the menu. If the bitmap is to be used for defining a cursor, one of the squares in the images may be designated as the hotspot. This determines where the cursor is actually pointing. For cursors with sharp tips (such as arrows or fingers), this is usually at the end of the tip; for symmetric cursors (such as crosses or bullseyes), this is usually at the center. Bitmaps are stored as small C code fragments suitable for including in applications. They provide an array of bits as well as symbolic con- stants giving the width, height, and hotspot (if specified) that may be used in creating cursors, icons, and tiles. The WIDTHxHEIGHT argument gives the size to use when creating a new bit- map (the default is 16x16). Existing bitmaps are always edited at their current size. If the bitmap window is resized by the window manager, the size of the squares in the grid will shrink or enlarge to fit. Options bitmap accepts the following options: -help This option will cause a brief description of the allowable options and parameters to be printed. -display display This option specifies the name of the X server to used. -geometry geometry This option specifies the placement and size of the bitmap window on the screen. See X for details. -nodashed This option indicates that the grid lines in the work area should not be drawn using dashed lines. Although dashed lines are prettier than solid lines, on some servers they are significantly slower. -name variablename This option specifies the variable name to be used when writ- ing out the bitmap file. The default is to use the basename of the filename command line argument. -bw number This option specifies the border width in pixels of the main window. -fn font This option specifies the font to be used in the buttons. -fg color This option specifies the color to be used for the fore- ground. -bg color This option specifies the color to be used for the back- ground. -hl color This option specifies the color to be used for highlighting. -bd color This option specifies the color to be used for the window border. -ms color This option specifies the color to be used for the pointer (mouse). bmtoa accepts the following option: -chars cc This option specifies the pair of characters to use in the string version of the bitmap. The first character is used for 0 bits and the second character is used for 1 bits. The default is to use dashes (-) for 0's and sharp signs (#) for 1's. atobm accepts the following options: -chars cc This option specifies the pair of characters to use when con- verting string bitmaps into arrays of numbers. The first character represents a 0 bit and the second character represents a 1 bit. The default is to use dashes (-) for 0's and sharp signs (#) for 1's. -name variable This option specifies the variable name to be used when writ- ing out the bitmap file. The default is to use the basename of the filename command line argument or leave it blank if the standard input is read. -xhot number This option specifies the X coordinate of the hotspot. Only positive values are allowed. By default, no hotspot informa- tion is included. -yhot number This option specifies the Y coordinate of the hotspot. Only positive values are allowed. By default, no hotspot informa- tion is included. Changing grid squares Grid squares may be set, cleared, or inverted by pointing to them and clicking one of the buttons indicated below. Multiple squares can be changed at once by holding the button down and dragging the cursor across them. Set squares are filled and represent 1's in the bitmap; clear squares are empty and represent 0's. Button 1 This button (usually leftmost on the pointer) is used to set one or more squares. The corresponding bit or bits in the bitmap are turned on (set to 1) and the square or squares are filled. Button 2 This button (usually in the middle) is used to invert one or more squares. The corresponding bit or bits in the bitmap are flipped (1's become 0's and 0's become 1's). Button 3 This button (usually on the right) is used to clear one or more squares. The corresponding bit or bits in the bitmap are turned off (set to 0) and the square or squares are emp- tied. Menu commands To make defining shapes easier, bitmap provides 13 commands for drawing whole sections of the grid at once, 2 commands for manipulating the hotspot, and 2 commands for updating the bitmap file and exiting. A com- mand button for each of these operations is located to the right of the grid. Several of the commands operate on rectangular portions of the grid. These areas are selected after the command button is pressed by moving the cursor to the upper left square of the desired area, pressing a pointer button, dragging the cursor to the lower right hand corner (with the button still pressed) , and then releasing the button. The command may be aborted by pressing any other button while dragging or by releas- ing outside the grid. To invoke a command, move the pointer over that command and click any button. ClearAll This command is used to clear all of the bits in the bitmap as if Button 3 had been dragged through every square in the grid. It cannot be undone. SetAll This command is used to set all of the bits in the bitmap as if Button 1 had been dragged through every square in the grid. It cannot be undone. InvertAll This command is used to invert all of the bits in the bitmap as if Button 2 had been dragged through every square in the grid. ClearArea This command is used to clear a region of the grid as if But- ton 3 had been dragged through each of the squares in the region. When this command is invoked, the cursor will change shape to indicate that the area to be cleared should be selected as outlined above. SetArea This command is used to set a region of the grid as if Button 1 had been dragged through each of the squares in the region. When this command is invoked, the cursor will change shape to indicate that the area to be set should be selected as out- lined above. InvertArea This command is used to invert a region of the grid as if Button 2 had been dragged through each of the squares in the region. When this command is invoked, the cursor will change shape to indicate that the area to be inverted should be selected as outlined above. CopyArea This command is used to copy a region of the grid from one location to another. When this command is invoked, the cur- sor will change shape to indicate that the area to be copied should be selected as outlined above. The cursor should then be clicked on the square to which the upper left hand corner of the region should be copied. MoveArea This command is used to move a region of the grid from one location to another. When this command is invoked, the cur- sor will change shape to indicate that the area to be moved should be selected as outlined above. The cursor should then be clicked on the square to which the upper left hand corner of the region should be moved. Any squares in the region's old position that are not also in the new position are cleared. OverlayArea This command is used to copy all of the set squares in a region of the grid from one location to another. When this command is invoked, the cursor will change shape to indicate that the area to be copied should be selected as outlined above. The cursor should then be clicked on the square to which the upper left hand corner of the region should be overlaid. Only the squares that are set in the region will be touched in the new location. Line This command will set the squares in a line between two points. When this command is invoked, the cursor will change shape to indicate that the pointer should be clicked on the two end points of the line. Circle This command will set the squares on a circle specified by a center and a point on the curve. When this command is invoked, the cursor will change shape to indicate that the pointer should be clicked on the center of the circle and then over a point on the curve. Small circles may not look very round because of the size of the grid and the limits of having to work with discrete pixels. FilledCircle This command will set all of the squares in a circle speci- fied by a center and a point on the curve. When this command is invoked, the cursor will change shape to indicate that the pointer should be clicked on the center of the circle and then over a point on the curve. All squares side and includ- ing the circle are set. FloodFill This command will set all clear squares in an enclosed shape. When this command is invoked, the cursor will change shape to indicate that the pointer should be clicked on any empty square inside the shape to be filled. All empty squares that border horizontally or vertically with the indicated square are set out to the enclosing shape. If the shape is not closed, the entire grid will be filled. Set Hot Spot This command designates one square in the grid as the hot spot if this bitmap is to be used for defining a cursor. When the command is invoked, the cursor will change indicat- ing that the pointer should be clicked on the square to con- tain the hot spot. Clear Hot Spot This command removes any designated hot spot from the bitmap. WriteOutput This command writes a small fragment of C code representing the bitmap to the filename specified on the command line. If the file already exists, the original file will be renamed to filename before the new file is created. If an error occurs in either the renaming or the writing of the bitmap file, a dialog box will appear asking whether or not bitmap should use /tmp/filename instead. Quit This command causes bitmap to display a dialog box asking whether or not it should save the bitmap (if it has changed) and then exit. Answering yes is the same as invoking Write Output; no causes bitmap to simply exit; and cancel will abort the Quit command so that more changes may be made. File format The Write Output command stores bitmaps as simple C program fragments that can be compiled into programs, referred to by X Toolkit pixmap resources, manipulated by other programs (see xsetroot), or read in using utility routines in the various programming libraries. The width and height of the bitmap as well as the hotspot, if specified, are written as preprocessor symbols at the start of the file. The bitmap image is then written out as an array of characters: #define name_width 11 #define name_height 5 #define name_x_hot 5 #define name_y_hot 2 static char name_bits[] = { 0x91, 0x04, 0xca, 0x06, 0x84, 0x04, 0x8a, 0x04, 0x91, 0x04 }; The name prefix to the preprocessor symbols and to the bits array is con- structed from the filename argument given on the command line. Any directories are stripped off the front of the name and any suffix begin- ning with a period is stripped off the end. Any remaining non-alphabetic characters are replaced with underscores. The namexhot and nameyhot symbols will only be present if a hotspot has been designated using the Set Hot Spot command. Each character in the the array contains 8 bits from one row of the image (rows are padded out at the end to a multiple of 8 to make this possi- ble). Rows are written out from left to right and top to bottom. The first character of the array holds the leftmost 8 bits of top line, and the last character holds the right most 8 bits (including padding) of the bottom line. Within each character, the leftmost bit in the bitmap is the least significant bit in the character. This process can be demonstrated visually by splitting a row into words containing 8 bits each, reversing the bits each word (since Arabic num- bers have the significant digit on the right and images have the least significant bit on the left), and translating each word from binary to hexadecimal. In the following example, the array of 1's and 0's on the left represents a bitmap containing 5 rows and 11 columns that spells X11. To its right is the same array split into 8 bit words with each row padded with 0's so that it is a multiple of 8 in length (16): 10001001001 10001001 00100000 01010011011 01010011 01100000 00100001001 00100001 00100000 01010001001 01010001 00100000 10001001001 10001001 00100000 Reversing the bits in each word of the padded, split version of the bit- map yields the left hand figure below. Interpreting each word as hexade- cimal number yields the array of numbers on the right: 10010001 00000100 0x91 0x04 11001010 00000110 0xca 0x06 10000100 00000100 0x84 0x04 10001010 00000100 0x8a 0x04 10010001 00000100 0x91 0x04 The character array can then be generated by reading each row from left to right, top to bottom: static char name_bits[] = { 0x91, 0x04, 0xca, 0x06, 0x84, 0x04, 0x8a, 0x04, 0x91, 0x04 }; The bmtoa program may be used to convert bitmap files into arrays of characters for printing or including in text files. The atobm program can be used to convert strings back to bitmap format. Using bitmaps in programs The format of bitmap files is designed to make bitmaps and cursors easy to use within X programs. The following code could be used to create a cursor from bitmaps defined in this.cursor and this_mask.cursor: #include "this.cursor" #include "this_mask.cursor" XColor foreground, background; /* fill in foreground and background color structures */ Pixmap source = XCreateBitmapFromData (display, drawable, this_bits, this_width, this_height); Pixmap mask = XCreateBitmapFromData (display, drawable, this_mask_bits, this_mask_width, this_mask_height); Cursor cursor = XCreatePixmapCursor (display, source, mask, foreground, background, this_x_hot, this_y_hot); Additional routines are available for reading in bitmap files and return- ing the data in the file, in Bitmap (single-plane Pixmap for use with routines that require stipples), or full depth Pixmaps (often used for window backgrounds and borders). Applications writers should be careful to understand the difference between Bitmaps and Pixmaps so that their programs function correctly on color and monochrome displays. For backward compatibility, bitmap will also accept X10 format bitmap files. However, when the file is written out again it will be in X11 format. X defaults bitmap uses the following resources: Background The window's background color. Bits which are 0 in the bit- map are displayed in this color. This option is useful only on color displays. The default value is ``white''. BorderColor The border color. This option is useful only on color dis- plays. The default value is ``black''. BorderWidth The border width. The default value is 2. BodyFont The text font. The default value is variable. Dashed If ``off'', then bitmap will draw the grid lines with solid lines. The default is ``on''. Foreground The foreground color. Bits which are 1 in the bitmap are displayed in this color. This option is useful only on color displays. The default value is ``black''. Highlight The highlight color. bitmap uses this color to show the hot spot and to indicate rectangular areas that will be affected by the Move Area, Copy Area, Set Area, Clear Area, and Invert Area commands. If a highlight color is not given, then bit- map will highlight by inverting. This option is useful only on color displays. Mouse The pointer (mouse) cursor's color. This option is useful only on color displays. The default value is ``black''. Geometry The size and location of the bitmap window. Dimensions The WIDTHxHEIGHT to use when creating a new bitmap. See also X(X), Xlib - C Language X Interface (particularly the section on ``Mani- pulating Bitmaps''), ``XmuReadBitmapDataFromFile'' Known Limitations The old command line arguments are not consistent with other X programs. If you move the pointer too fast while holding a pointer button down, some squares may be missed. This is caused by limitations in how fre- quently the X server can sample the pointer location. There is no way to write to a file other than the one specified on the command line. There is no way to change the size of the bitmap once the program has started. There is no undo command.