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2 FONTS 2.1 INTRODUCTION In the previous chapters when we have printed text with help of the low level Text() function or the high level IntuiText structure, we have always used a font called "Topaz". The reason why we always have used this font is simply because it is the Amiga's default font and exist in ROM. Topaz is, however, not the only font available on the Amiga. There exist thousands more, but these are not placed in ROM, they are loaded from disks. Loading fonts from disks is luckily quite a simple task since all necessary functions have already been written and exist in the "Diskfont Library". In this chapter I will show you how to open the Diskfont Library, and use its functions. This involves finding out which fonts are available, loading them into memory and how to use them. I will also explain how to create your own fonts and use them in your own programs. 2.2 FONTS A font is a collection of graphical objects that represents characters. Since the Amiga was built as a graphical work station the system has been designed to handle all different types of fonts with great efficiency. Fonts of almost any size can be used, and the Amiga can itself convert fonts to styles like italic, underlined, bold, extended, and all possible All fonts have a "Baseline" on which the characters are placed. Characters like "abcdef" will all be on and above the baseline. On the other hand, characters like "gjpqy" will also use some space under the baseline. Here are three letters - 'a' 'b' and 'g'. As you can see will the 'g' use same space below the baseline. (The baseline is like normal rows on a paper.) # # #### # # # # # # # ##### ##### ##### # # # # # # # # # # # # # # # # # # # # # # # # ###### ##### ##### <= Baseline # # # # #### 2.3 ROM FONTS As said above, there exist for the moment only one ROM based font on the Amiga. It is Topaz and exist in two sizes, 8 and 9 pixels high. (ROM is like the normal memory in a computer, but when the computer is turned off the contents will still be intact. The disadvantage is that you can not change anything which is stored in ROM. ROM - "Read Only Memory".) Topaz two sizes: - 9 pixels high (32 characters/row low resolution) (64 - " - high resolution) - 8 pixels high (40 - " - low resolution) (80 - " - high resolution) Note! The limit on how many characters/row you can print simply depends on the width of the screen. In the above example I assume that low resolution means a 320 pixels wide display, and high resolution 640 pixels wide screen. Nowadays you can not be sure what the maximum width is simply because many users are now working on displays with overscan, extra large screens, see previous chapter for more information. I my self is currently using a 736 pixels wide and 540 lines tall display. 2.3.1 TEXTATTR STRUCTURE When you want to use a font you allocate a TextAttr structure (defined in the header file "graphics/text.h"). In the structure you write your requirements, the name of the font, height, style (normal, underlined, bold, italic...) and what type it is (if the font exist in ROM or on Disk). The TextAttr structure look like this: struct TextAttr { STRPTR ta_Name; UWORD ta_YSize; UBYTE ta_Style; UBYTE ta_Flags; }; ta_Name: Name of the font together with the extension ".font". For example: To get the font Topaz you should write "topaz.font". ta_YSize: The Height of the font. To get a 9 pixel high font simply write 9. ta_Style: There exist five different styles that may be combined. The styles are: Normal, Underlined, Bold Italic and Extended. You specify which styles you want to use with the following flags: FS_NORMAL, FSF_UNDERLINED, FSF_BOLD, FSF_ITALIC and FSF_EXTENDED. To get a combination (e.g. Bold and Italic) use the binary OR operator "|" (e.g. FSF_BOLD | FSF_ITALIC). Note! If you ask for an underlined font for example, it is not sure there exist one. You should then get the font you want in the normal style, and then change it with help of the SetSoftStyle() function. (Explained later in this chapter.) ta_Flags: This field tells the Amiga what type of font you want. If it is a ROM based font write FPF_ROMFONT. If it is a disk based font write FPF_DISKFONT. (See below for a complete Flag list.) If you want to use the ROM font Topaz, 9 pixels high, normal style, you should initialize the TextAttr structure like this: struct TextAttr my_font_attr= { "topaz.font", /* Name of the font. */ 9, /* Height (in pixels) */ FS_NORMAL, /* Style */ FPF_ROMFONT /* Exist in ROM. */ }; 2.3.2 OPEN ROM FONTS After you have initialized the TextAttr structure you call the OpenFont() function to get access to a ROM font. The Amiga will open the font which closes matches your requirements in the TaxtAttr structure. If OpenFont() finds the font it returns a pointer to a TextFont structure and tells the system that you are using the font. Synopsis: font = OpenFont( attr ); font: (struct TextFont *) Pointer to a TextFont structure which is declared in header file "graphics/text.h". See below for more information about this structure. If OpenFont() could not find the font it returns NULL. attr: (struct TextAttr *) Pointer to an already initialized TextAttr structure. OpenFont() will try to open the font which closes matches your requirements. 2.3.3 CLOSE ROM FONTS All fonts you have opened must be "closed" before your program terminates! Since the font is in ROM no memory would be wasted if you forgot to close a previously opened font, but your program code would not look very good, so be careful. Close a font by calling the CloseFont() function. Synopsis: CloseFont( font ); font: (struct TextFont *) Pointer to a previously opened TextFont structure. Note that you should NOT try to close a font which you have not opened! 2.4 DISK FONTS Most fonts does not exist in ROM but are loaded from disks. The greatest advantage of loading fonts rather than including the fonts with the program itself is that several programs running at the same time can all use the same set of fonts. A lot of memory is therefore saved. 2.4.1 DISKFONT LIBRARY Most of the special routines which are involved with loading and using disk fonts are automatically taken care of by the Diskfont Library. Whenever you want to use disk fonts you should remember to open this library. The diskfont library is opened as all other libraries with an OpenLibrary() call, and closed by and CloseLibrary() call. If the diskfont library not have already been opened by some other program it will be loaded from the system disk. (From the logical device "LIBS:", named "diskfont.library". Here is an example: struct Library *DiskfontBase; DiskfontBase = (struct DiskfontBase *) OpenLibrary( "diskfont.library", 0 ); if( !DiskfontBase ) clean_up( "Could not open Diskfont library!" ); ... if( DiskfontBase ) CloseLibrary( DiskfontBase ); 2.4.2 FINDING OUT WHICH FONTS ARE AVAILABLE After you have opened the diskfont library you can use the special function AvailFonts() which will scan through the font directory of the system disk, and return a complete list of available fonts. Synopsis: missing = AvailFonts( buffer, size, type ); missing: (long) If the buffer was not big enough to store the complete list of fonts in the extra number of bytes needed is returned. If 0 is returned the buffer was big enough for a complete list of fonts. buffer: (char *) Pointer to some memory were the list of fonts can be stored. size: (long) The size of the buffer (in bytes). type: (long) If you want to look for available fonts which are already in the memory set the flag "AFF_MEMORY". If you want to search the disk for available fonts, set the flag "AFF_DISK". To search both the memory and the disk set both flags with the binary OR operator between ("AFF_DISK | AFF_MEMORY"). The font list consists of a AvailFontsHeader structure followed by a list of AvailFonts structures (both declared in header file "libraries/diskfont.h"): struct AvailFontsHeader { UWORD afh_NumEntries; }; afh_NumEntries: Number of AvailFonts structures. struct AvailFonts { UWORD af_Type; struct TextAttr af_Attr; }; af_Type: If the font exist in memory the "AFF_MEMORY" flag is set. If the font exist on the disk the "AFF_DISK" flag is set. af_Attr: An initialized TextAttr structure. This structure can be examined to find the font's name, size, style etc... (See above for more information about the TextAttr structure.) It is impossible to know how big memory buffer you need for the AvailFonts() function. You can of course allocate a very big buffer and be quite sure it will be big enough, but this is not a good solution. A lot of memory is wasted if the buffer is too big, and it may happen that the buffer still is too small. The solution to this problem is to call the AvailFonts() function with the buffer size set to 0. AvailFonts() will then return the number of bytes needed to store the complete list. Allocate a buffer with this size, and call the AvailFonts() function once again, but this time give it the new buffer. Here is an example: int size; struct AvailFontsHeader *avail_fonts_header; struct AvailFonts *avail_fonts; /* Find out which fonts are available both in the memory */ /* as well on the disk. The buffer size is set to 0, hence */ /* the function will return the correct number of bytes */ /* needed to store the complete list in: */ size = AvailFonts( NULL, 0, AFF_DISK | AFF_MEMORY ); /* Allocate the buffer: (Now we know what size is needed.) */ avail_fonts_header = (struct AvailFontsHeadr *) AllocMem( size, MEMF_CLEAR ); /* Call the function AvailFonts() again, but this time we give */ /* it a buffer to store the information in: (Remember to still */ /* check that the buffer was big enough! Some other task could */ /* have changed something in the FONTS: device while we */ /* allocated the buffer. Never trust the Amiga...) */ if( AvailFonts( avail_fonts_header, size, AFF_DISK | AFF_MEMORY ) ) clean_up( "Buffer to small to store the font list in!" ); /* We can now examine the list. See example 5. */ When the Amiga tries to load a font it looks in the logical device "FONTS:". If you have more fonts on another disk you can reassign the logical device "FONTS:" with help of the AmigaDOS command "Assign". If you have a collection of nice fonts in the drawer "MyFonts" on the disk in "df1:" you call Assign like this: "Assign FONTS: df1:MyFonts" (without quotations) 2.4.3 OPEN DISK FONTS You "open" a disk font by initializing a TextAttr structure with your requirements and call the OpenDiskFont() function. Remember that the diskfont library must have been opened before you may use this or the AvailFonts() function. If the font have not already been loaded into the memory by some other program it will automatically be done. Synopsis: font = OpenDiskFont( attr ); font: (struct TextFont *) Pointer to a TextFont structure which is declared in header file "graphics/text.h". See below for more information about this structure. attr: (struct TextAttr *) Pointer to an already initialized TextAttr structure. OpenDiskFont() will try to open the font which closes matches your requirements. 2.4.4 CLOSE DISK FONTS All fonts you have opened must be closed before your program terminates. A lot of memory is otherwise wasted. Please be very careful with this! You close a font with the CloseFont() function as described above. Both ROM and Disk fonts are closed with this function. Synopsis: CloseFont( font ); font: (struct TextFont *) Pointer to a previously opened TextFont structure. Note that you should NOT try to close a font which you have not opened! 2.5 USE THE NEW FONTS Once you have successfully opened the desired fonts you may start to use them. As described in the beginning of this chapter you can either use the low level functions Move() and Text() or the high level IntuiText structures. 2.5.1 HIGH LEVEL The high level approach is a clean and nice way to print text. For short messages it can be a bit tedious since you need to use some structures just to print some text. These structures that can feel a bit complicated and unnecessary are extremely useful and easy to handle if a lot of text is needed. The advantage with these structures is that they can easily be combined with each other as well as with other objects like gadgets, requesters, etc... Here is what you have to do: 1. Initialize a TextAttr structure with your requirements as described above. 2. Open the desired font as have also been described above. 3. Initialize the IntuiText structures as normal (see chapter 3 Graphics) but set the ITextFont pointer to the desired TextAttr structure. 4. Either connect the IntuiTedxt structure to an object (gadget, requester etc...) or print it directly with help of the PrintIText() function. Here is an example: ("my_window" is a pointer to an already opened window.) /* Pointer to the diskfont library: */ struct Library *DiskfontBase; /* The attributes for our desired font: */ struct TextAttr my_font_attr= { "Courier.font", /* Name of the font. */ 18, /* Height, 18 pixels tall. */ FS_NORMAL, /* Style, normal. */ FPF_DISKFONT /* Load it from the disk. */ }; /* Intuition's text structure: */ struct IntuiText my_intui_text= { 1, /* FrontPen, colour register 1. */ 2, /* BackPen, colour register 2. */ JAM2, /* DrawMode, draw the characters with colour 1, */ /* on a colour 2 background. */ 10, 20, /* LeftEdge, TopEdge. Position of the text. */ &my_font_attr, /* ITextFont, use the Courier font. */ "Hello", /* IText, the text that will be printed. */ NULL, /* NextText, last structure in the list. */ }; /* Open the Intuition Library, windows etc... */ /* Open the DiskFont library: */ DiskfontBase = (struct DiskfontBase *) OpenLibrary( "diskfont.library", 0 ); if( !DiskfontBase ) clean_up( "Could not open Diskfont library!" ); /* Open the desired font: */ font = OpenDiskFont( &my_font_attr ); /* Tell Intuition to print the text: */ PrintIText( my_window->RPort, &my_intui_text, 0, 0 ); /* Close the DiskFont Library: */ if( DiskfontBase ) CloseLibrary( DiskfontBase ); /* Close the window, Intuition Library etc... */ 2.5.2 LOW LEVEL When it is very little text that should be printed, or you do not want to mess around with structures you can use the low level functions Move() and Text(). Before you can use these functions you have to (of course) open the font as normal, but also tell the RastPort to use the new font. Use the SetFont() function to change a RastPort's default font. Synopsis: error = SetFont( rp, font ); error: (long) If OK 0 is returned, else an error number is returned which means something went wrong. rp: (struct RastPort *) Pointer to the RastPort that should be affected. font: (struct TextFont *) Pointer to a TextFont structure which has previously been "opened". The the first character of the text will be printed at the Rastport's (cp_x, cp_y) coordinate. (The current cp_x and cp_y values can be found in the Rastport structure. see chapter 12 LOWLEVELGRAPHICS for more information about Rastports). To change the printing position use the function Move() with a pointer to the Rastport that should be affected and the new coordinate as parameters. Synopsis: Move( rast_port, x, y ); rast_port: (struct RastPort *) Pointer to the Rastport that should be affected. x: (long) The new X position. y: (long) The new Y position. When a character is printed the base line will be placed at the current cp_x, cp_y coordinate. The point below which is marked with a star (*) is the coordinate for the first character. 00000000000000000000000 00000000010000000000000 00000000010000000000000 00111100010000000000000 00000010010000000000000 00000010010000000000000 00000010010000000000000 00111110011111000111110 01000010010000101000010 01000010010000101000010 01000010010000101000010 01000010010000101000010 *0111111011111000111110 <= Base line 00000000000000000000010 00000000000000000000010 00000000000000001000010 00000000000000000111100 00000000000000000000000 If the base line is 13 lines below the top of the character, you must set the Y coordinate to 13 or higher, or the top part of the characters will not fit. 2.2.2 PRINT TEXT To print text on the Amiga you can use the low level Text() function which supports fonts of all sizes and all styles (more about this later). To print text you need a pointer to the Rastport which should be affected, a pointer to a text string and finally a value that tells Text() how many characters of the string should be printed. Only one line each call may be printed, and no formatting, word-wrapping etc is done. The Rastports current font will be used. Synopsis: Text( rast_port, string, nr_of_chr ); rast_port: (struct RastPort *) Pointer to the RastPort that should be affected. string: (char *) Pointer to a text string that will be printed. nr_of_chr: (long) The number of characters that should be printed. Here is an example that prints "Hello" on the display: Text( &my_rast_port, "HELLO", 5 ); The high level IntuiText structure also supports different types of fonts. See chapter 3 Graphics for more information about this structure and how to use it. 2.6 STYLES When you set your requirements in the TextAttr structure you can among many things specify what style (bold, underlined, italic, extended or a combination) you want the font to be in. If you are luck the font with your specified style exist. If not you can let the Amiga change the font into desired style by calling the SetSoftStyle() function. Before you use the SetSoftStyle() function you should call the AskSoftStyle() function to check if you are allowed to change the font as desired. The routines for changing the font style may not work very good with some fonts, and you are therefore sometimes advised not to change the style. For the moment there exist five different styles you may use. The header file "graphics/text.h" has defined them as: FS_NORMAL Normal style. FSF_EXTENDED Extra wide characters. FSF_ITALIC Italic (characters leaning to the right). FSF_BOLD Extra thick characters. FSF_UNDERLINED Underlined characters. To produce a combination of the styles you simply put the binary operator OR (|) between the flags. Note that you should always first try to load the font with the desired style. It is only when the desired style does not exist you should try to modify it with the SetSoftStyle() function. Synopsis: a_style = AskSoftStyle( rast_port ) a_style: (UWORD) The function returns a bit field where the allowed style bits for the checked font are set. This value should be used as a parameter when you call the SetSoftStyle() function. rast_port: (struct RastPort *) Pointer to the rastport to which the font you want to check is connected. Once you know which styles you may use you can change the font by calling the SetSoftStyle() function. Synopsis: new_style = SetSoftStyle( rast_port, style, a_style ); new_style: (UWORD) The function will only create the styles it is allowed to do (see a_styles), and it may therefore happen that the function will not generate all of the styles you wanted. This returned value tells us which style bits it used. rast_port: (struct RastPort *) Pointer to the rastport to which the font you want to change is connected. style: (UWORD) The desired style. a_style: (UWORD) The styles you may use. This value was returned by AskSoftStyle(). If you want to be able to use all styles and do not care if some styles would look strange set this field to 0xFFFF (all styles allowed). This can result in some very ugly styles, and is therefore not recommended. Here is an example: UWORD style; /* Desired style. */ UWORD a_style; /* Styles allowed. */ UWORD new_style; /* Style we got. */ /* Set the desired style: (A combination of underlined, */ /* bold and italic.) */ style = FSF_UNDERLINED | FSF_BOLD | FSF_ITALIC; /* Check which styles we may use: */ a_style = AskSoftStyle( my_window->RPort ); /* Change the window's font style: */ new_style = SetSoftStyle( my_window->RPort, style, a_style ); /* Tell the user what style we will use: */ printf( "Style:" ); if( new_style ) printf( "%s%s%s!\n", new_style & FSF_UNDERLINED ? " Underlined" : "", new_style & FSF_BOLD ? " Bold" : "", new_style & FSF_ITALIC ? " Italic" : "" ); else printf( " normal!" ); printf( "!\n" ); 2.7 CREATING YOUR OWN FONTS If you want to create a new font yourself you should use the font editor program ("fed") which is included on the "Extras" disk you received when you bought your Amiga. To create your own fonts without this types of utility is very complicated. However, if you want to create a very small font set with a very limited number of characters it is possible to do it. I will here explain how to do this since it is rather interesting and good to know how a font set is actually constructed. If you want to include a font set together with your program code you do actually not need to do very much. I have written a small utility called PrintFont (in drawer "Include Font") which will load a specified font and print all information about it in C code. This code can then simply be included in your own program code. A font consists of: 1. A TextFont structure to which all other information of the font is connected to. 2. A memory area where the graphics of the font's characters are declared. (Character data) 3. A list of data which tells us where each character's fontdata begins and how wide each character is. 4. If it is a proportional font (each character has it's own width, for example an "i" is not as wide as a "W") we need information about how much space is needed between each character when printed. (Character Space). All proportional fonts does not need this array. If it does not exist the nominal width (tf_XSpace) will be used. 5. Finally, if the font is proportional we also need information about how many pixels to the right each character should be placed inside the the "character space". All proportional fonts does not need this array. If it does not exist the kerning (x offset) will be 0. 2.7.1 TEXTFONT STRUCTURE The TextFont structure which is declared in header file "graphics/text.h" is the foundation of all fonts. It consists of all information which is needed for the system to be able to print the characters. The structure looks like this: struct TextFont { struct Message tf_Message; UWORD tf_YSize; UBYTE tf_Style; UBYTE tf_Flags; UWORD tf_XSize; UWORD tf_Baseline; UWORD tf_BoldSmear; UWORD tf_Accessors; UBYTE tf_LoChar; UBYTE tf_HiChar; APTR tf_CharData; UWORD tf_Modulo; APTR tf_CharLoc; APTR tf_CharSpace; APTR tf_CharKern; }; tf_Message: The top part of the text font structure consists of a message are. It is used by the system to communicate with other parts of the system. If the font is removed for example, a message is sent to all involved parts of the system. The Message structure is defined in header file "exec/ports.h" as: struct Message { struct Node mn_Node; struct MsgPort *mn_ReplyPort; UWORD mn_Length; }; The Node structure is defined in header file "exec/nodes.h" as: struct Node { struct Node *ln_Succ; struct Node *ln_Pred; UBYTE ln_Type; BYTE ln_Pri; char *ln_Name; }; See chapter 16 "Messages" for more information about these structures. If you want to initialize your own TextFont structure you should set the ln_Succ and ln_Pred field of the Node structure to NULL. The ln_Type to "NT_FONT" (font node), the ln_Pri to 0 (normal priority), and finally the ln_Name to a string which contains the name of the font. The mn_ReplyPort pointer of the Message structure should be set to NULL (Exec will take care of this later), and the length to the number of bytes is needed to store the whole font (including this structure, the name, and the arrays described below). tf_YSize: The height of the font (number of pixels/lines). tf_Style: The style bits as described above: FS_NORMAL Normal style. FSF_EXTENDED Extra wide characters. FSF_ITALIC Italic. FSF_BOLD Extra thick characters. FSF_UNDERLINED Underlined characters. tf_Flags: The font's special flags: FPF_ROMFONT The font is located in the ROM. FPF_DISKFONT The font is loaded from a disk. All fonts you design yourself must have this flag set unless you intend to burn your own memory chips. FPF_REVPATH The font should be printed in the opposite direction (right to left). FPF_TALLDOT The font is specially designed for high resolution screens with no interlace. (Each pixel is only half as wide as it is tall.) FPF_WIDEDOT The font is specially designed for low resolution screens which are interlaced. (Each pixel is only half as tall as it is wide.) FPF_PROPORTIONAL The font is proportional. The width of each character will vary depending on how wide the character is itself. The box containing an "i" will (usually) not be as wide as a "w" for example. FPF_DESIGNED If you have designed the font for the size specified in the "tf_ YSize" field this flag should be set. If a program has constructed this size of the font the flag should not be set. (The graphical quality of a Constructed font is usually not as good as a font which has been designed for this size.) FPF_REMOVED This flag is set by the system when it has been removed. tf_XSize: The nominal width of each character. If the font is normal (non proportional) this is the width between the first pixels of two characters. If a proportional font is used a special array of different width for each character may be used. tf_Baseline: The number of pixels down the baseline is from the top of the characters. You may not use a base line which is greater than the nominal height - 1 (tf_YSize-1), or the system may crash! tf_BoldSmear: When you change the style to bold by calling the SetSoftStyle() function a copy of the font is placed on top of itself and a bit to the right. The further to the right, the bolder characters. This value represents the number of pixels to the right the characters should be moved. This value is usually set to 1, but large fonts usually need larger values. tf_Accessors: Several programs may use the same font simultaneously, and this value represents the current number of users. Each time the font is opened by a program this value is increased, and each time some one closes the font this value is decreased. tf_LoChar: A font can consist of up to 256 characters, but usually the font is much smaller. You can for example have a font which only consists of capital letters (A, B, C, .. Y, Z). This field tells us and the system which is the first character. In our example the value would be set to 65 (ASCII 65 = 'A'). tf_HiChar: The last character in this font. In our example above this value would be set to 90 (ASCII 90 = 'Z'). tf_CharData: Pointer to the character data (the graphics). See below for more information. tf_Modulo: The graphics (character data) for the characters are organized into lines. First comes the top line of all characters, then the second line and so on... This value represents the number of bytes needed for each line. tf_CharLoc: Pointer to a list of data which tells us where each character's data begins and how wide each character is. tf_CharSpace: Pointer to an array of space information - how much space is needed between each character when printed. If this pointer is NULL the nominal width (tf_XSpace) will be used for all characters. tf_CharKern: Pointer to an array of kerning data - how many pixels to the right the character should be moved inside its box (character space) when printed. If the pointer is NULL the kerning (x offset) will be 0. 2.7.2 FONT (CHARACTER) DATA The graphics for the characters are organized into an array of bit packed character data organized into words. Let's say we want to create our own font of five characters - A, B, C, D, and E. They should look like this: **** ***** **** **** ****** ** * ** * ** * ** * ** ** * ** * ** ** * ** ****** ***** ** ** * ***** ** * ** * ** ** * ** ** * ** * ** * ** * ** ** * ***** **** **** ****** Although our font consist of five characters, we must also define an extra one which will be used when an non existing character is printed. If we try to print the character G which does not exist, this special character will be printed. This character is usually referred as the "not in this font character". In our example we will use a black box which looks like this: ******** ******** ******** ******** ******** ******** ******** ******** The characters should now be translated into C code. This is easiest done if you write the characters on a grid paper and organizes them into groups of four squares. Each group (binary values) can then easily be translated into hexadecimal as the following table shows: (Each marked square on your paper represents the digit '1' and each empty square represents the digit `0') Bin Hex --------- 0000 0 0001 1 0010 2 0011 3 0100 4 0101 5 0110 6 0111 7 1000 8 1001 9 1010 A 1011 B 1100 C 1101 D 1110 E 1111 F In our example our characters would be translated like this: ------------------------------------------------------------------------- A B C D E * A B C D E * ------------------------------------------------------------------------- 00111100 01111100 00111100 01111000 01111110 11111111 3C 7C 3C 78 7E FF 01100010 01100010 01100010 01100100 01100000 11111111 62 62 62 64 60 FF 01100010 01100010 01100000 01100010 01100000 11111111 62 62 60 62 60 FF 01111110 01111100 01100000 01100010 01111100 11111111 7E 7C 60 62 7C FF 01100010 01100010 01100000 01100010 01100000 11111111 62 62 60 62 60 FF 01100010 01100010 01100010 01100100 01100000 11111111 62 62 62 64 60 FF 01100010 01111100 00111100 01111000 01111110 11111111 62 7C 3C 78 7E FF 00000000 00000000 00000000 00000000 00000000 11111111 00 00 00 00 00 FF ------------------------------------------------------------------------- Finally we put the hexadecimal values into an array of words: /* The font data: */ UWORD MyOwnFontData[24]= { 0x3C7C,0x3C78,0x7EFF, /* Row 0 */ 0x6262,0x6264,0x60FF, /* " 1 */ 0x6262,0x6062,0x60FF, /* " 2 */ 0x7E7C,0x6062,0x7CFF, /* " 3 */ 0x6262,0x6062,0x60FF, /* " 4 */ 0x6262,0x6264,0x60FF, /* " 5 */ 0x627C,0x3C78,0x7EFF, /* " 6 */ 0x0000,0x0000,0x00FF /* " 7 */ }; 2.7.3 CHARACTER LOCATION Secondly we need to tell the computer where each character exist in the character data, and how wide the character is. In our example all characters had the same width (8 pixels), but if we use a proportional font each character may have its own width. For every character two words are needed. The first word represents the offset position (the location of the character in the character data). The second word represents the width (in bits) of the character. In our example the character A has the offset value 0 since it is the first character. The second character (B) has the offset value 8 since the A was 8 bits wide. The third character has the offset value 16 (in hexadecimal it is 10) since both A and B was each 8 bits wide, and so on... All this information is stored in an array of "longs" (two words). /* The location and width of each character: */ ULONG MyOwnFontLoc[5]= { 0x00000008, /* A: Offset 0[hex], Width 8 bits */ 0x00080008, /* B: Offset 8[hex], Width 8 bits */ 0x00100008, /* C: Offset 10[hex], Width 8 bits */ 0x00180008, /* D: Offset 18[hex], Width 8 bits */ 0x00200008 /* E: Offset 20[hex], Width 8 bits */ }; 2.7.4 CHARACTER SPACE Normally the default width (tf_XSize) is used as the space between the first pixel of two character. If the tf_Size is 12, the second character will be printed 12 pixels to the right and so on... However, if you are using a proportional font, each character may have its own space. The tf_CharSpace field should in this case point to an array of words where each word represents the space of one character. If the tf_CharSpace field is NULL the nominal width will be used. (See illustration "Proportional Fonts".) In our example we used a normal (non proportional) font, and hence we do not need any array of space information. 2.7.5 CHARACTER KERNING Some proportional fonts are using "kerning", which is a list of offset values. These offset values represent the number of pixels each character will be moved to the right inside its own character space. The tf_CharKern field must contain the address of this kerning list of words, or the kerning value 0 will be used. (See illustration "Proportional Fonts".) In our example we used a normal (non proportional) font, and hence we do not need any array of kerning data. 2.7.6 OUR OWN FONT EXAMPLE In our example the complete C code should look like this: #include <exec/types.h> #include <graphics/text.h> /* The font data: */ UWORD MyOwnFontData[24]= { 0x3C7C,0x3C78,0x7EFF, /* Row 0 */ 0x6262,0x6264,0x60FF, /* " 1 */ 0x6262,0x6062,0x60FF, /* " 2 */ 0x7E7C,0x6062,0x7CFF, /* " 3 */ 0x6262,0x6062,0x60FF, /* " 4 */ 0x6262,0x6264,0x60FF, /* " 5 */ 0x627C,0x3C78,0x7EFF, /* " 6 */ 0x0000,0x0000,0x00FF /* " 7 */ }; /* The location and width of each character: */ ULONG MyOwnFontLoc[5]= { 0x00000008, /* A: Offset 0[hex], Width 8 bits */ 0x00080008, /* B: Offset 8[hex], Width 8 bits */ 0x00100008, /* C: Offset 10[hex], Width 8 bits */ 0x00180008, /* D: Offset 18[hex], Width 8 bits */ 0x00200008 /* E: Offset 20[hex], Width 8 bits */ }; /* The text font structure: */ struct TextFont MyOwnFontFont= { { /* Message */ { /* Node */ NULL, /* ln_Succ */ NULL, /* ln_Pred */ NT_FONT, /* ln_Type */ 0, /* ln_Pri */ "OurFont.font" /* ln_Name */ }, NULL, /* mn_ReplyPort */ 72 /* mn_Length */ }, 8, /* tf_YSize */ 0, /* tf_Style */ 66, /* tf_Flags */ 8, /* tf_XSize */ 6, /* tf_Baseline */ 1, /* tf_BoldSmear */ 0, /* tf_Accessors */ 65, /* tf_LoChar */ 69, /* tf_HiChar */ (APTR) &MyOwnFontData, /* tf_CharData */ 6, /* tf_Modulo */ (APTR) &MyOwnFontLoc, /* tf_CharLoc */ NULL, /* tf_CharSpace */ NULL, /* tf_CharKern */ }; 2.8 FUNCTIONS OpenFont() This function is used to get access to a ROM font. You initialize a TextAttr structure with your requirements, and send a pointer to it as the only parameter. If OpenFont() finds the font it returns a pointer to a TextFont structure and tells the system that you are using the font. Remember to close all fonts you have opened with the CloseFont() function. Synopsis: font = OpenFont( attr ); font: (struct TextFont *) Pointer to a TextFont structure or NULL if OpenFont() could not find the font. attr: (struct TextAttr *) Pointer to an initialized TextAttr structure. OpenFont() will try to open the font which closes matches your requirements. CloseFont() All fonts you have opened with the OpenFont() function must be "closed" before your program terminates! You close ROM fonts by calling the CloseFont() function. Synopsis: CloseFont( font ); font: (struct TextFont *) Pointer to a previously opened TextFont structure. Note that you should NOT try to close a font which you have not opened! AvailFonts() This function will scan through the font directory of the system disk, and return a complete list of available fonts. Note that you must have opened the DiskFont Library before you may call this function. Synopsis: missing = AvailFonts( buffer, size, type ); missing: (long) If the buffer was not big enough to store the complete list of fonts in the extra number of bytes needed is returned. If 0 is returned the buffer was big enough for a complete list of fonts. buffer: (char *) Pointer to some memory were the list of fonts can be stored. size: (long) The size of the buffer (in bytes). type: (long) If you want to look for available fonts which are already in the memory set the flag "AFF_MEMORY". If you want to search the disk for available fonts, set the flag "AFF_DISK". To search both the memory and the disk set both flags with the binary OR operator between: "AFF_DISK | AFF_MEMORY". OpenDiskFont() To load fonts from the disk and open them use the OpenDiskFont() function. Note that you must have opened the DiskFont Library before you may call this function. Remember to close all fonts you have opened! Synopsis: font = OpenDiskFont( attr ); font: (struct TextFont *) Pointer to a TextFont structure or NULL if OpenFont() could not find the font. attr: (struct TextAttr *) Pointer to an initialized TextAttr structure. OpenDiskFont() will try to open the font which closes matches your requirements. SetFont() This function will change a RastPort's font. The font must of course have been successfully opened before you may start to use it. Synopsis: error = SetFont( rp, font ); error: (long) If OK 0 is returned, else an error number is returned which means something went wrong. rp: (struct RastPort *) Pointer to the RastPort that should be affected. font: (struct TextFont *) Pointer to a TextFont structure which has previously been "opened". AskSoftStyle() This function tells us how a specified font may be changed, and which styles may be automatically created. Use the function SetSoftStyle() to later change style. The reason why you have to check if you are allowed to alter the style is that some fonts may look very bad when altered. Note that you should always first try to load the font with the desired style. It is only when the desired style does not exist you should try to modify it with the SetSoftStyle() function. Synopsis: a_style = AskSoftStyle( rast_port ) a_style: (UWORD) The function returns a bit field where the allowed style bits for the checked font are set. This value should be used as a parameter when you later call the SetSoftStyle() function. rast_port: (struct RastPort *) Pointer to the rastport to which the font you want to check is connected. SetSoftStyle() This function will alter the style of a specified font. You should first find out which styles you may alter by calling the AskSoftStyle() function before you call this function. Synopsis: new_style = SetSoftStyle( rp, style, a_style ); new_style: (UWORD) The function will only create the styles it is allowed to do (see a_styles), and it may therefore happen that the function will not generate all of the styles you wanted. This returned value tells us which style bits it used. rp: (struct RastPort *) Pointer to the rastport to which the font you want to change is connected. style: (UWORD) The desired style. a_style: (UWORD) The styles you may use. This value was returned by AskSoftStyle(). If you want to be able to use all styles and do not care if some styles would look strange set this field to 0xFFFF (all styles allowed). This can result in some very ugly styles, and is therefore not recommended. ClearEOL() This function will clear the area to the right of the current position. The height of the area which is cleared is set to fit the current font height. Synopsis: ClewarEOL( rp ); rp: (struct RastPort *) Pointer to a rastport. The area from the current position to the right edge of the rastport is cleared. The height of the area depends on the current font size. Normally is the cleared area set to colour 0, but if you are using draw mode "JAM2" will the area be filled with the BgPen colour. ClearScreen() This function will clear the area to the right of the current position and the area below. Synopsis: ClewarScreen( rp ); rp: (struct RastPort *) Pointer to a rastport. The area from the current position to the right edge of the rastport is cleared. The area below is also cleared. Normally is the cleared area set to colour 0, but if you are using draw mode "JAM2" will the area be filled with the BgPen colour. TextLength() This function will return the number of pixels wide the text string would be if printed with the rastport's current font. Synopsis: width = TextLength( rp, string, nr_chars ); width: (long) Number of pixels wide the text string would be if printed with the rastport's current font. rp: (struct RastPort *) Pointer to the rastport. string: (char *) Pointer to the string containing the text you want to measure. nr_chars: (long) Number of characters in the string that should be counted. 2.9 EXAMPLES Example 1 This example shows how to open the ROM font "Topaz". (Topaz is the standard system font, and is placed in ROM on all Amigas. If you have told preferences to use a 60-character display the 9 pixel size will be used, else (80-character display) the 8 pixel size will be used. This example prints some text in both sizes. Example 2 This example demonstrates how to change the style of a font. We will open the ROM font "Topaz" and change the style to underlined, bold and italic. Well, we try to use all mentioned styles, but it may happen that we are not allowed to use some styles. Example 3 This example demonstrates how to open a disk font (Opal, 12) and prints some characters with the new font in a window. Note! The font "Opal" must exist in the systems FONT: directory or you will receive an error message! Example 4 This example opens disk fonts and prints some interesting information about them. (Height, width, flags, style, etc...) Syntax: Example4 [font1] [font2] [font3] ... (The largest size of each font will be used.) Example 5 This example demonstrates how to use the AvailFonts() function. All available fonts (both on the disk as well as in the memory) will be listed together with some useful information about them. Example 6 This example demonstrates how you can use a font loaded from a disk in your own Intuition programs.