12 Text Building Block

Text Building Block To: From: Date: Subject: Users of the TOOlKit's Text Building BloCk 21 Marcr! 1984 How to use the Text Building Block (TK8E) (draft version 3) ==============================================:====================-========:== When reading this document it is suggested that you have a copy of the UText interface available for reference. The Text Building Block allows users to specify an LRect in their view irl w~ii:~;ri m..Jltiple paragraphs may be entered either from the keyooara or pasted frOlT tne clipboard. "i thin this box, te>tt klill word klrap based on the bounos of t!'"l~ b:JY and optional 1ndentation fields 1n the TPara=ornet object. Trlese fields oe-foiJl t to zero, thus if the values are not Changed, the text kl1ll fit tig!"ltly 11.:1 tnir: the LRect specified. (Currently only left justified text is supported so trtere klill be a ragged right edge.) Application programmers must create a TTextlmage for eaCh separate grouo Of te~t they wiSh to display. The CREATE method expects an LReet within its vie~. Ir: adOi tion, the 1sGro~le ooolea!! parameter speCifies Whether or not tr,e LRect can grow at the bottom if text that is oisplayea cannot fit in the spe:ifiEJ LRect. Textlmages display TText Objects. A TText Object contains a list Of TParagr~~ oOjects. EaCh TParaglaph Object contains the characters ana typeStyle 1nformation for one paragraprl. Associated wit~ eaCh paragraph is a TParaImage wrl1c~ 1s stored 1n a list Of TParaImages in TTextlnage. A TParaImage cO;ltains all Of the display specific information about a particular paragraptl suerl a~ where each line ends and tne pixel height of the displayed paragratJn. Wrte:-I a TIextlmage is created, 1t nust have an 1nit1al TText object. Ttle next oeject, in turn, rust nave at least one paragraph 1n its paragraph l1st. Also, eaCf, paragrap~ points to a TParaFormat, Whicrl spec1fies margins, taos, paragraph spacing and other formatting Characteristics. TParaFormats are stored in a TStyleSheet, WhiCh is simply a list Of TParaFormats. Since the list is an indexed list, one can store commonly U$eo form&ts at known posi tioras in ttte list for rapia retrieval when reformatting a part1CUlar paragraph. Typically, app11cations store a single styleSrleet in a fie10 Of their applicat10n windOW. Eacn TText ooject, 1n adaition to containing a 11st -Of paragraphS also points to a styleSheet. By storing ttle styleSheet in the w1naow, eaCh next Object can refer-ence tr.e sarne styleStleet. Text Butldlrtg BlOCk ••••••••••••••.•••.•.••.•..•..•...•....•.....••••.•.....•.•..••.....•••.•................... PaQe 1 The typical order of allocation is then: Create a waraFormat. tnen create a TStyleSheet and install the paraFormat in its list. Set TAppllnaow.styleSheet to tne ne:J) stylesr'eet. create a paragraptl, passing the paraFormat just createa. Create a next ObJect and install the parag~ just created in its paragraphs list and trle set styleSheet field to the new styleSheet. Now cr…