Gecko:LineBreakerAPI - Revision history

Roc: /* Suggestion */

2006-11-17T10:11:57Z

Suggestion

← Older revision		Revision as of 10:11, 17 November 2006
Line 34:		Line 34:
	* of text. The text is a sequence of text chunks. The chunks with		* of text. The text is a sequence of text chunks. The chunks with
	* mNeedBreakData set to true get break data computed for them and then		* mNeedBreakData set to true get break data computed for them and then
	* set by calling SetBreaks on the chunk.		* set by calling SetBreaks on the chunk. The chunks with mNeedBreakData set
			* to false are included so that the line breaking algorithm can get all the
			* context it might need.
	*/		*/
	void ComputeLineBreaks(const TextChunk* aTextChunks, PRUint32 aNumChunks);		void ComputeLineBreaks(const TextChunk* aTextChunks, PRUint32 aNumChunks);
	};		};

Roc: /* Overview */

2006-11-17T10:10:10Z

Overview

← Older revision		Revision as of 10:10, 17 November 2006
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	* The run of text can contain text from different DOM nodes		* The run of text can contain text from different DOM nodes
	* We only need to compute linebreaks for some parts of the text (for other parts of the text we already know the linebreaks or there can't be linebreaks because of CSS white-space override)		* We only need to compute linebreaks for some parts of the text (for other parts of the text we already know the linebreaks or there can't be linebreaks because of CSS white-space override)
	* There should only be ONE linebreaker algorithm seen by layout. If we need language-specific behaviour, the linebreaker should implement that internally.		* There should only be ONE linebreaker algorithm seen by layout. If we need language-specific behaviour, the linebreaker should implement that internally. So Thai text will have to be handled by detecting Thai characters and applying the Thai algorithm to the Thai parts of the string.

	=== Suggestion ===		=== Suggestion ===

Roc: /* Suggestion */

2006-11-17T10:05:38Z

Suggestion

← Older revision		Revision as of 10:05, 17 November 2006
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	/* aBreakBefore points to mLength + 1 bytes, set to PR_TRUE if we can		/* aBreakBefore points to mLength + 1 bytes, set to PR_TRUE if we can
	break before the corresponding character of mText. This gets called		break before the corresponding character of mText. This gets called
	only if mNeedBreakData is true.		only if mNeedBreakData is true. aBreakBefore[mLength] is set to PR_TRUE
			if we can break after this chunk.
	The intent is that layout will subclass TextChunk and override		The intent is that layout will subclass TextChunk and override
	SetBreaks to store the break data into the textrun object associated		SetBreaks to store the break data into the textrun object associated

Roc: /* Suggestion */

2006-11-17T10:03:50Z

Suggestion

← Older revision		Revision as of 10:03, 17 November 2006
Line 21:		Line 21:
	/* aBreakBefore points to mLength + 1 bytes, set to PR_TRUE if we can		/* aBreakBefore points to mLength + 1 bytes, set to PR_TRUE if we can
	break before the corresponding character of mText. This gets called		break before the corresponding character of mText. This gets called
	only if mNeedBreakData is true. */		only if mNeedBreakData is true.
	virtual void SetBreaks(~~TextChunk* aChunk,~~ PRPackedBool* aBreakBefore) = 0;		The intent is that layout will subclass TextChunk and override
			SetBreaks to store the break data into the textrun object associated
			with this text chunk.
			*/
			virtual void SetBreaks(PRPackedBool* aBreakBefore) = 0;
	};		};

Roc at 02:09, 17 November 2006

2006-11-17T02:09:33Z

← Older revision		Revision as of 02:09, 17 November 2006
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	enum { CHAR, UNICHAR } mCharacterType;		enum { CHAR, UNICHAR } mCharacterType;
	PRPackedBool mNeedBreakData;		PRPackedBool mNeedBreakData;

	/* aBreakBefore points to mLength + 1 bytes, set to PR_TRUE if we can		/* aBreakBefore points to mLength + 1 bytes, set to PR_TRUE if we can
	break before the corresponding character of mText. This gets called		break before the corresponding character of mText. This gets called

Roc at 02:09, 17 November 2006

2006-11-17T02:09:12Z

← Older revision		Revision as of 02:09, 17 November 2006
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	PRUint32 mLength;		PRUint32 mLength;
	enum { CHAR, UNICHAR } mCharacterType;		enum { CHAR, UNICHAR } mCharacterType;
	PRPackedBool* mBreakOutput; /* mLength + 1 bytes, set to PR_TRUE if we can		PRPackedBool mNeedBreakData;
	break before the corresponding character of
	mText. ~~Can be null, meaning we don't need to~~		/* aBreakBefore points to mLength + 1 bytes, set to PR_TRUE if we can
	~~know the breakability of this text chunk~~. */		break before the corresponding character of mText. This gets called
			only if mNeedBreakData is true. */
			virtual void SetBreaks(TextChunk* aChunk, PRPackedBool* aBreakBefore) = 0;
	};		};

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	* Asks the linebreaker to compute line break opportunities for a block		* Asks the linebreaker to compute line break opportunities for a block
	* of text. The text is a sequence of text chunks. The chunks with		* of text. The text is a sequence of text chunks. The chunks with
	* ~~non-null mBreakOutput~~ get break ~~opportunities~~ computed for them and		* mNeedBreakData set to true get break data computed for them and then
	* ~~stored in~~ the ~~array pointed to by mBreakOutput~~.		* set by calling SetBreaks on the chunk.
	*/		*/
	void ComputeLineBreaks(const TextChunk* aTextChunks, PRUint32 aNumChunks);		void ComputeLineBreaks(const TextChunk* aTextChunks, PRUint32 aNumChunks);
	};		};

Roc at 02:04, 17 November 2006

2006-11-17T02:04:14Z

← Older revision		Revision as of 02:04, 17 November 2006
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	};		};

			/**
			* Asks the linebreaker to compute line break opportunities for a block
			* of text. The text is a sequence of text chunks. The chunks with
			* non-null mBreakOutput get break opportunities computed for them and
			* stored in the array pointed to by mBreakOutput.
			*/
	void ComputeLineBreaks(const TextChunk* aTextChunks, PRUint32 aNumChunks);		void ComputeLineBreaks(const TextChunk* aTextChunks, PRUint32 aNumChunks);
	};		};

Roc at 02:02, 17 November 2006

2006-11-17T02:02:36Z

← Older revision		Revision as of 02:02, 17 November 2006
Line 22:		Line 22:
	know the breakability of this text chunk. */		know the breakability of this text chunk. */
	};		};

	void ComputeLineBreaks(const TextChunk* aTextChunks, PRUint32 aNumChunks);		void ComputeLineBreaks(const TextChunk* aTextChunks, PRUint32 aNumChunks);
	};		};

Roc at 02:02, 17 November 2006

2006-11-17T02:02:19Z

New page

== New Linebreaking API ==

=== Overview ===

* Compute linebreaks for a run of text with one API call, where the run of text begins and ends with either a known line-break or non-text content
* The run of text can contain text from different DOM nodes
* We only need to compute linebreaks for some parts of the text (for other parts of the text we already know the linebreaks or there can't be linebreaks because of CSS white-space override)
* There should only be ONE linebreaker algorithm seen by layout. If we need language-specific behaviour, the linebreaker should implement that internally.

=== Suggestion ===

class nsLineBreaker {
public:
struct TextChunk {
nsIAtom* mLanguageHint;
const void* mCharacters;
PRUint32 mLength;
enum { CHAR, UNICHAR } mCharacterType;
PRPackedBool* mBreakOutput; /* mLength + 1 bytes, set to PR_TRUE if we can
break *before* the corresponding character of
mText. Can be null, meaning we don't need to
know the breakability of this text chunk. */
};

void ComputeLineBreaks(const TextChunk* aTextChunks, PRUint32 aNumChunks);
};