Technical Q&A's

QTMTB 05 - New Display Flags (1-May-95)

The display flags control the behavior of the Text Media Handler. The Text Media Handler is responsible for rendering the text. These flags provide additional control over the rendering process. To change the Text Media Handler's behavior with these flags, you will normally add these flags to each text sample. When the Text Media Handler reads each sample, it will also read the associated flags. The Text Media Handler will then adjust its behavior according to the display flag.

To add a text sample to the media, you use the routines AddTESample and AddTextSample. To add display flags to a text sample, you pass them in the displayFlags parameter of these routines.

enum {
dfContinuousScroll 	= 1<<9,
dfFlowHoriz 		= 1<<10,
dfDropShadow 		= 1<<12,
dfAntiAlias 		= 1<<13,
dfKeyedText 		= 1<<14
};

dfContinuousScroll is a display flag that tells the Apple Text Media Handler to let new samples cause previous samples to scroll out. dfScrollIn and/or dfScrollOut must also be set for this to take effect.

dfFlowHoriz is a display flag that tells the Apple Text Media Handler to let horizontally scrolled text flow within the text box. This behavior contrasts with letting text flow as if the text box had no right edge.

dfDropShadow is a display flag that tells the Apple Text Media Handler to support true drop shadows. Using SetTextSampleData, the position and translucency of the drop shadow is under application control.

dfAntiAlias is a display flag that tells the Apple Text Media Handler to attempt to display text anti-aliased. While anti-aliased text looks nicer, it incurs a significant performance penalty.

dfKeyedText is a display flag that tells the Apple Text Media Handler to render text over the background without drawing the background color. This technique is otherwise known as "Masked Text."

findTextUseOffset is a new find text flag that instructs FindNextText to look at the value pointed to by the offset parameter and start the search at that offset into the text sample indicated by startTime. This allows you to continue a text search from within a given sample, so that multiple occurrences of the search string can be found within a single sample.

findTextUseOffset = 16

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