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ICU-2405 code review changes.

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X-SVN-Rev: 11915
This commit is contained in:
Eric Mader 2003-05-13 23:02:45 +00:00
parent 4d8b16de1c
commit 3d7ae2b1f1
6 changed files with 202 additions and 94 deletions
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19
icu4c/source/layout/LEFontInstance.cpp
View File

@ -12,10 +12,29 @@
*/
#include "LETypes.h"
#include "LEScripts.h"
#include "LEFontInstance.h"
U_NAMESPACE_BEGIN
const char LEFontInstance::fgClassID=0;
const LEFontInstance *LEFontInstance::getSubFont(const LEUnicode chars[], le_int32 *start, le_int32 limit,
le_int32 script, LEErrorCode &success) const
{
if (LE_FAILURE(success)) {
return NULL;
}
if (chars == NULL || *start < 0 || limit < 0 || *start >= limit || script < 0 || script >= scriptCodeCount) {
success = LE_ILLEGAL_ARGUMENT_ERROR;
return NULL;
}
*start = limit;
return this;
}
void LEFontInstance::mapCharsToGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count,
le_bool reverse, const LECharMapper *mapper, LEGlyphID glyphs[]) const
{

154
icu4c/source/layout/LEFontInstance.h
View File

@ -16,13 +16,14 @@ U_NAMESPACE_BEGIN
/**
* Instances of this class are used by LEFontInstance::mapCharsToGlyphs and
* LEFontInstance::mapCharToGlyph to adjust character codes before the character
* to glyph mapping process. Examples of this are filtering out control charcters
* to glyph mapping process. Examples of this are filtering out control characters
* and character mirroring - replacing a character which has both a left and a right
* hand form with the opposite form.
*
* @draft ICU 2.2
*/
class LECharMapper /* not : public UObject because this is an interface/mixin class */ {
class LECharMapper /* not : public UObject because this is an interface/mixin class */
{
public:
/**
* Destructor.
@ -33,7 +34,7 @@ public:
/**
* This method does the adjustments.
*
* @param ch - the input charcter
* @param ch - the input character
*
* @return the adjusted character
*
@ -43,18 +44,31 @@ public:
};
/**
* This is a pure virtual base class that servers as the interface between a LayoutEngine
* This is a virtual base class that servers as the interface between a LayoutEngine
* and the platform font environment. It allows a LayoutEngine to access font tables, do
* character to glyph mapping, and obtain metrics information without knowing any platform
* specific details. There are also a few utility methods for converting between points,
* pixels and funits. (font design units)
*
* Each instance of an LEFontInstance represents a renerable instance of a font. (i.e. a
* single font at a particular point size, with a particular transform)
* An instance of an <code>LEFontInstance</code> represents a font at a particular point
* size. Each instance can represent either a single physical font, or a composite font.
* A composite font is a collection of physical fonts, each of which contains a subset of
* the characters contained in the composite font.
*
* @draft ICU 2.2
* Note: with the exception of <code>getSubFont</code>, the methods in this class only
* make sense for a physical font. If you have an <code>LEFontInstance</code> which
* represents a composite font you should only call the methods below which have
* an <code>LEGlyphID</code>, an <code>LEUnicode</code> or an <code>LEUnicode32</code>
* as one of the arguments because these can be used to select a particular subfont.
*
* Subclasses which implement composite fonts should supply an impelmentation of these
* methods with some default behavior such as returning constant values, or using the
* values from the first subfont.
*
* @draft ICU 2.6
*/
class U_LAYOUT_API LEFontInstance /* not : public UObject because this is an interface/mixin class */ {
class U_LAYOUT_API LEFontInstance : public UObject
{
public:
/**
@ -66,44 +80,65 @@ public:
virtual inline ~LEFontInstance() {};
/**
* This method is provided so that clients can tell if
* a given LEFontInstance is an instance of a composite
* font.
*
* @return <code>true</code> if the instance represents a composite font, <code>false</code> otherwise.
* Get a physical font which can render the given text. For composite fonts,
* if there is no single physical font which can render all of the text,
* return a physical font which can render an initial substring of the text,
* along with the limit offset of that substring.
*
* Internally, the LayoutEngine works with runs of text all in the same
* font and script, so it is best to call this method with text which is
* in a single script, passing the script code in as a hint. If you don't
* know the script of the text, you can pass <code>zyyyScriptCode</code>,
* which is the script code for characters used in more than one script.
*
* The default implementation of this method is intended for instances of
* <code>LEFontInstance</code> which represent a physical font. It returns
* <code>this</code> and indicates that the entire string can be rendered.
*
* Sublcasses which implement composite fonts must override this method.
* Where it makes sense, they should use the script code as a hint to render
* characters from the COMMON script in the font which is used for the given
* script. For example, if the input text is a series of Arabic words separated
* by spaces, and the script code passed in is <code>arabScriptCode</code> you
* should return the font used for Arabic characters for all of the text.
*
* @param chars - the array of Unicode characters.
* @param start - a pointer to the starting offset in the text. On exit this
* will be set the the limit offset of the text which can be
* rendered using the returned font.
* @param limit - the limit offset for the input text.
* @param script - the script hint.
* @param success - set to an error code if the arguments are illegal, or no font
* can be returned for some reason. May also be set to
* <code>LE_NO_SUBFONT_WARNING</code> if there is no subfont which
* can render the text.
*
* @return an <code>LEFontInstance</code> for the sub font which can render the characters, or
* <code>NULL</code> if there is an error.
*
* @see LEScripts.h
*
* @draft ICU 2.6
*/
virtual le_bool isComposite() const;
/**
* Get a sub-font for a run of text from a composite font. This method examines the
* given text, finding a run of text which can all be rendered
* using the same sub-font. Subclassers should try to keep all the text in a single
* sub-font if they can.
*
* @param chars - the array of unicode characters
* @param offset - a pointer to the starting offset in the text. This will be
* set to the limit offset of the run on exit.
* @param count - the number of characters in the array. Can be used as a hint for selecting a sub-font.
* @param script - the script of the characters.
*
* @return an <code>LEFontInstance</code> for the sub font which can render the characters.
*
* @draft ICU 2.6
*/
virtual const LEFontInstance *getSubFont(const LEUnicode chars[], le_int32 *offset, le_int32 count, le_int32 script) const;
virtual const LEFontInstance *getSubFont(const LEUnicode chars[], le_int32 *start, le_int32 limit, le_int32 script, LEErrorCode &success) const;
//
// Font file access
//
/**
* This method reads a table from the font.
* This method reads a table from the font. Note that in general,
* it only makes sense to call this method on an <code>LEFontInstance</code>
* which represents a physical font - i.e. one which has been returned by
* <code>getSubFont()</code>. This is because each subfont in a composite font
* will have different tables, and there's no way to know which subfont to access.
*
* @param tableTag - the four byte table tag
* Sublcasses which represent composite fonts should always return <code>NULL</code>.
*
* @return the address of the table in memory
* @param tableTag - the four byte table tag. (e.g. 'cmap')
*
* @return the address of the table in memory, or <code>NULL</code>
* if the table doesn't exist.
*
* @draft ICU 2.2
*/
@ -138,8 +173,8 @@ public:
* indices, using the font's character to glyph map.
*
* @param chars - the character array
* @param offset - the index of the first charcter
* @param count - the number of charcters
* @param offset - the index of the first character
* @param count - the number of characters
* @param reverse - if true, store the glyph indices in reverse order.
* @param mapper - the character mapper.
* @param glyphs - the output glyph array
@ -152,7 +187,7 @@ public:
/**
* This method maps a single character to a glyph index, using the
* font's charcter to glyph map. The default implementation of this
* font's character to glyph map. The default implementation of this
* method calls the mapper, and then calls <code>mapCharToGlyph(mappedCh)</code>.
*
* @param ch - the character
@ -160,20 +195,22 @@ public:
*
* @return the glyph index
*
* @see LECharMapper
*
* @draft ICU 2.6
*/
virtual LEGlyphID mapCharToGlyph(LEUnicode32 ch, const LECharMapper *mapper) const;
/**
* This method maps a single character to a glyph index, using the
* font's charcter to glyph map.
* font's character to glyph map. There is no default implementation
* of this method because it requires information about the platform
* font implementation.
*
* @param ch - the character
*
* @return the glyph index
*
* @see LECharMapper
*
* @draft ICU 2.6
*/
virtual LEGlyphID mapCharToGlyph(LEUnicode32 ch) const = 0;
@ -377,7 +414,7 @@ public:
//
// These methods won't ever be called by the LayoutEngine,
// but are useful for cleints of <code>LEFontInstance</code> who
// but are useful for clients of <code>LEFontInstance</code> who
// need to render text.
//
@ -418,19 +455,30 @@ public:
* @draft ICU 2.6
*/
virtual le_int32 getLineHeight() const;
/**
* ICU "poor man's RTTI", returns a UClassID for the actual class.
*
* @draft ICU 2.2
*/
virtual inline UClassID getDynamicClassID() const { return getStaticClassID(); }
/**
* ICU "poor man's RTTI", returns a UClassID for this class.
*
* @draft ICU 2.2
*/
static inline UClassID getStaticClassID() { return (UClassID)&fgClassID; }
private:
/**
* The address of this static class variable serves as this class's ID
* for ICU "poor man's RTTI".
*/
static const char fgClassID;
};
inline le_bool LEFontInstance::isComposite() const
{
return false;
}
inline const LEFontInstance *LEFontInstance::getSubFont(const LEUnicode /*chars*/[], le_int32 *offset, le_int32 count, le_int32 /*script*/) const
{
*offset += count;
return this;
}
inline le_bool LEFontInstance::canDisplay(LEUnicode32 ch) const
{
return mapCharToGlyph(ch) != 0;

4
icu4c/source/layout/LETypes.h
View File

@ -112,7 +112,7 @@ typedef le_uint16 TTGlyphID;
* the glyph ID within the font. The next 8 bits are
* the sub-font ID within a compound font. The high-
* order 8 bits are client defined. The LayoutEngine
* will never change or look at these bits.
* will never change or look at the client defined bits.
*
* @draft ICU 2.6
*/
@ -325,7 +325,7 @@ typedef struct LEPoint LEPoint;
*/
enum LEErrorCode {
/* informational */
// none right now...
LE_NO_SUBFONT_WARNING = U_USING_DEFAULT_WARNING,
/* success */
LE_NO_ERROR = U_ZERO_ERROR,

6
icu4c/source/layoutex/ParagraphLayout.cpp
View File

@ -590,10 +590,10 @@ void ParagraphLayout::computeSubFonts(const FontRuns *fontRuns)
for (run = 0; run < styleRunCount; run += 1) {
const LEFontInstance *runFont = fontRuns->getFont(si[0]);
le_int32 script = fScriptRuns->getValue(si[1]);
le_int32 count;
LEErrorCode success = LE_NO_ERROR;
while ((count = styleRunLimits[run] - offset) > 0) {
const LEFontInstance *subFont = runFont->getSubFont(fChars, &offset, count, script);
while (offset < styleRunLimits[run]) {
const LEFontInstance *subFont = runFont->getSubFont(fChars, &offset, styleRunLimits[run], script, success);
subFontRuns->add(subFont, offset);
}

24
icu4c/source/samples/layout/ScriptCompositeFontInstance.cpp
View File

@ -19,6 +19,8 @@
#include "ScriptCompositeFontInstance.h"
const char ScriptCompositeFontInstance::fgClassID=0;
ScriptCompositeFontInstance::ScriptCompositeFontInstance(FontMap *fontMap)
: fFontMap(fontMap)
{
@ -58,16 +60,24 @@ le_bool ScriptCompositeFontInstance::getGlyphPoint(LEGlyphID glyph, le_int32 poi
return false;
}
const LEFontInstance *ScriptCompositeFontInstance::getSubFont(const LEUnicode chars[], le_int32 *offset, le_int32 count, le_int32 script) const
const LEFontInstance *ScriptCompositeFontInstance::getSubFont(const LEUnicode chars[], le_int32 *start, le_int32 limit, le_int32 script, LEErrorCode &success) const
{
LEErrorCode status = LE_NO_ERROR;
const LEFontInstance *result = fFontMap->getScriptFont(script, status);
if (LE_FAILURE(status)) {
result = NULL;
if (LE_FAILURE(success)) {
return NULL;
}
*offset += count;
if (chars == NULL || *start < 0 || limit < 0 || *start >= limit || script < 0 || script >= scriptCodeCount) {
success = LE_ILLEGAL_ARGUMENT_ERROR;
return NULL;
}
const LEFontInstance *result = fFontMap->getScriptFont(script, success);
if (LE_FAILURE(success)) {
return NULL;
}
*start = limit;
return result;
}

89
icu4c/source/samples/layout/ScriptCompositeFontInstance.h
View File

@ -24,33 +24,47 @@ public:
virtual ~ScriptCompositeFontInstance();
/**
* This method is provided so that clients can tell if
* a given LEFontInstance is an instance of a composite
* font.
*
* @return <code>true</code> if the instance represents a composite font, <code>false</code> otherwise.
* Get a physical font which can render the given text. For composite fonts,
* if there is no single physical font which can render all of the text,
* return a physical font which can render an initial substring of the text,
* along with the limit offset of that substring.
*
* Internally, the LayoutEngine works with runs of text all in the same
* font and script, so it is best to call this method with text which is
* in a single script, passing the script code in as a hint. If you don't
* know the script of the text, you can pass <code>zyyyScriptCode</code>,
* which is the script code for characters used in more than one script.
*
* The default implementation of this method is intended for instances of
* <code>LEFontInstance</code> which represent a physical font. It returns
* <code>this</code> and indicates that the entire string can be rendered.
*
* Sublcasses which implement composite fonts must override this method.
* Where it makes sense, they should use the script code as a hint to render
* characters from the COMMON script in the font which is used for the given
* script. For example, if the input text is a series of Arabic words separated
* by spaces, and the script code passed in is <code>arabScriptCode</code> you
* should return the font used for Arabic characters for all of the text.
*
* @param chars - the array of Unicode characters.
* @param start - a pointer to the starting offset in the text. On exit this
* will be set the the limit offset of the text which can be
* rendered using the returned font.
* @param limit - the limit offset for the input text.
* @param script - the script hint.
* @param success - set to an error code if the arguments are illegal, or no font
* can be returned for some reason. May also be set to
* <code>LE_NO_SUBFONT_WARNING</code> if there is no subfont which
* can render the text.
*
* @return an <code>LEFontInstance</code> for the sub font which can render the characters, or
* <code>NULL</code> if there is an error.
*
* @see LEScripts.h
*
* @draft ICU 2.6
*/
virtual le_bool isComposite() const;
/**
* Get a sub-font for a run of text from a composite font. This method examines the
* given text, finding a run of text which can all be rendered
* using the same sub-font. Subclassers should try to keep all the text in a single
* sub-font if they can.
*
* @param chars - the array of unicode characters
* @param offset - a pointer to the starting offset in the text. This will be
* set to the limit offset of the run on exit.
* @param count - the number of characters in the array. Can be used as a hint for selecting a sub-font.
* @param script - the script of the characters.
*
* @return an <code>LEFontInstance</code> for the sub font which can render the characters.
*
* @draft ICU 2.6
*/
const LEFontInstance *getSubFont(const LEUnicode chars[], le_int32 *offset, le_int32 count, le_int32 script) const;
virtual const LEFontInstance *getSubFont(const LEUnicode chars[], le_int32 *start, le_int32 limit, le_int32 script, LEErrorCode &success) const;
/**
* This method maps a single character to a glyph index, using the
@ -86,14 +100,31 @@ public:
float getScaleFactorY() const;
/**
* ICU "poor man's RTTI", returns a UClassID for the actual class.
*
* @draft ICU 2.2
*/
virtual inline UClassID getDynamicClassID() const { return getStaticClassID(); }
/**
* ICU "poor man's RTTI", returns a UClassID for this class.
*
* @draft ICU 2.2
*/
static inline UClassID getStaticClassID() { return (UClassID)&fgClassID; }
protected:
FontMap *fFontMap;
};
inline le_bool ScriptCompositeFontInstance::isComposite() const
{
return true;
}
private:
/**
* The address of this static class variable serves as this class's ID
* for ICU "poor man's RTTI".
*/
static const char fgClassID;
};
inline const void *ScriptCompositeFontInstance::getFontTable(LETag tableTag) const
{