GEOS SDK TechDocs
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3 The Text Object Library
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3.2 Paragraph Attribute Definitions
The text object library provides a multitude of ways to shape the appearance of individual characters. Each character within a text object may even exhibit its own individual attributes, if the object is defined to use multiple character attributes. The definitions within this section show the full range of possibilities for character attributes.
The
VisTextCharAttr
structure provides a great variety of attributes for characters within text objects. Many of the
VisTextCharAttr
fields use graphics structures to tailor the appearance of individual characters within the text object. You may wish to review the Graphics Environment chapter to discover the full features of this structure.
Code Display 10-1 The VisTextCharAttr Structure
typedef struct {
StyleSheetElementHeader VTCA_meta;
FontID VTCA_fontID;
WBFixed VTCA_pointSize;
TextStyle VTCA_textStyles;
ColorQuad VTCA_color;
sword VTCA_trackKerning;
byte VTCA_fontWeight;
byte VTCA_fontWidth;
VisTextExtendedStyles VTCA_extendedStyles;
SystemDrawMask VTCA_grayScreen;
GraphicPattern VTCA_pattern;
ColorQuad VTCA_bgColor;
SystemDrawMask VTCA_bgGrayScreen;
GraphicPattern VTCA_bgPattern;
byte VTCA_reserved[7];
} VisTextCharAttr;
VTCA_
meta
stores a
StyleSheetElementHeader
. This structure field allows the
VisTextCharAttr
structure to act as an element in an element array. For complete information on using character attribute element arrays to implement character style runs, see Character Runs
.
VTCA_
fontID
stores the
FontID
of the font to be used for this character. Any current font allowed by the system is valid. There may exist up to 65536 fonts of type
FontID
.
VTCA_ pointSize stores the point size of the character. This may be any fixed point value between 4 and 792.
VTCA_
textStyles
stores the text styles (of type
TextStyle
) to be applied to this character. For a list of text styles, see the Drawing Shapes chapter.
VTCA_
color
stores the current color (of type
ColorQuad
) of the foreground text character.
VTCA_
trackKerning
stores the kerning value (either positive or negative) for this character. This value is expressed in points and reflects how much extra space (if positive) or removal of space (if negative) to apply between this character and the next character.
VTCA_
fontWeight
stores the font-weight (thickness) of the character. This value is expressed as a
FontWeight
value, a percentage between 75% and 125%.
VTCA_
fontWidth
stores the width of the font, expressed as a
FontWidth
value, a percentage between 25% and 200%. Several constants are defined in
font.h
with common font widths, including FWI_CONDENSED and FWI_EXPANDED.
VTCA_
extendedStyles
stores any
VisTextExtendedStyles
(separate from the
TextStyle
in VTCA_
textStyles
) in use by this character. These styles are defined in the text object library. See VisTextExtendedStyles
for a list of extended styles.
VTCA_
grayScreen
stores the
SystemDrawMask
to use when displaying this text. This mask is applied to the text characters but not to the background.
VTCA_
pattern
stores the
GraphicPattern
to use when displaying this text. This pattern is applied to the text characters but not to the background.
VTCA_bgColor
stores the background color to apply to the character's background (but not to the character itself).
VTCA_
bgGrayScreen
stores the
SystemDrawMask
to apply to the character's background.
VTCA_
bgPattern
stores the
GraphicPattern
to apply to the character's background.
Code Display 10-2 VisTextExtendedStyles
/* These flags are stored in the VisTextCharAttr entry VTCA_extendedStyles */ typedef WordFlags VisTextExtendedStyles; #define VTES_BOXED 0x8000 #define VTES_BUTTON 0x4000 #define VTES_INDEX 0x2000 #define VTES_ALL_CAP 0x1000 #define VTES_SMALL_CAP 0x0800 #define VTES_HIDDEN 0x0400 #define VTES_CHANGE_BAR 0x0200 #define VTES_BACKGROUND_COLOR 0x0100
VTES_BOXED draws the character within a box (a rectangle surrounding the character). If consecutive characters are marked VTES_BOXED they will all be drawn within a single rectangular outline.
VTES_BUTTON frames the text characters within a drop shadow. Consecutive characters marked VTES_BUTTON will be framed within a single drop-shadow.
VTES_INDEX marks the character for indexing purposes. This feature is currently not implemented.
VTES_ALL_CAP indicates that the character should be capitalized in the current point size.
VTES_SMALL_CAP indicates that the character should be capitalized, but at a smaller point size.
VTES_HIDDEN indicates that this character acts as hidden text. Hidden text may exhibit special properties (such as being masked out when printing).
VTES_CHANGE_BAR is currently unimplemented.
VTES_BACKGROUND_COLOR indicates that this character exhibits a special background color.
You may decide that you do not need your characters to exhibit the many attributes available within the
VisTextCharAttr
structure. If your text object is simple, you may want instead to use the default character attributes provided in the text object library. These default attributes supersede the use of the
VisTextCharAttr
structure. All of these attributes will fit into a single word record.
The
VisTextDefaultCharAttr
record allows your text object to exhibit three styles (underline, bold, and italic), 16 color indexes of type
Color
, eight point sizes, and 32 different fonts.
Code Display 10-3 VisTextDefaultCharAttr
typedef WordFlags VisTextDefaultCharAttr; #define VTDCA_UNDERLINE 0x8000 #define VTDCA_BOLD 0x4000 #define VTDCA_ITALIC 0x2000 #define VTDCA_COLOR 0x0f00 /* Color */ #define VTDCA_SIZE 0x00e0 /* VisTextDefaultSize */ #define VTDCA_FONT 0x001f /* VisTextDefaultFont */
#define VTDCA_COLOR_OFFSET 8 #define VTDCA_SIZE_OFFSET 5 #define VTDCA_FONT_OFFSET 0
typedef ByteEnum VisTextDefaultSize;
#define VTDS_8 0 /* Point size of 8 */
#define VTDS_9 1 /* Point size of 9 */
#define VTDS_10 2 /* Point size of 10 */
#define VTDS_12 3 /* Point size of 12 */
#define VTDS_14 4 /* Point size of 14 */
#define VTDS_18 5 /* Point size of 18 */
#define VTDS_24 6 /* Point size of 24 */
#define VTDS_36 7 /* Point size of 36 */
typedef ByteEnum VisTextDefaultFont;
#define VTDF_BERKELEY 0 /* Berkeley Font */
#define VTDF_CHICAGO 1 /* Chicago Font */
#define VTDF_BISON 2 /* Bison Font */
#define VTDF_WINDOWS 3 /* Windows Font */
#define VTDF_LED 4 /* LED Font */
#define VTDF_ROMA 5 /* Roma Font */
#define VTDF_UNIVERSITY 6 /* University Font */
#define VTDF_URW_ROMAN 7 /* URW Roman Font */
#define VTDF_URW_SANS 8 /* URW Sans Font */
#define VTDF_URW_MONO 9 /* URW Mono Font */
#define VTDF_URW_SYMBOLPS 10 /* URW Symbols Font */
#define VTDF_CENTURY_SCHOOLBOOK 11 /* Century Schoolbook Font */
#define VIS_TEXT_INITIAL_CHAR_ATTR \ ((VTDS_12 << VTDCA_SIZE_OFFSET) | VTDF_BERKELEY)
The text object library also provides several macros to make the definition of the
VisTextCharAttr
structure simpler. These macros are listed in VisTextCharAttr Macros
. In many cases, these macros make the definition of character style runs vastly easier.
Code Display 10-4 VisTextCharAttr Macros
#define CHAR_ATTR_STYLE_FONT_SIZE_STYLE_COLOR(ref, style, font, psize, tstyle, \ color) { \
{{{ref, 0}}, style}, font, {0, psize}, tstyle, \
{color, CF_INDEX, 0, 0}, 0, FWI_MEDIUM, FW_NORMAL, 0, SDM_100, {0}, \
{C_WHITE, CF_INDEX, 0, 0}, SDM_0, {0}, {0, 0, 0, 0, 0, 0, 0}}
#define CHAR_ATTR_FONT_SIZE_STYLE(font, psize, tstyle) \ CHAR_ATTR_STYLE_FONT_SIZE_STYLE_COLOR(2, CA_NULL_ELEMENT, font, \ psize, tstyle, C_BLACK)
#define CHAR_ATTR_FONT_SIZE(font, psize) \ CHAR_ATTR_STYLE_FONT_SIZE_STYLE_COLOR(2, CA_NULL_ELEMENT, font, \ psize, 0, C_BLACK)
GEOS SDK TechDocs
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| 3 The Text Object Library
| 3.2 Paragraph Attribute Definitions