private static void ScriptBreak(ScriptParagraph* scriptParagraph, char* chars,
SCRIPT_ITEM* scriptItems, int scriptItemCount)
{
SCRIPT_ITEM* scriptItem = scriptItems;
SCRIPT_ITEM* endScriptItem = scriptItems + scriptItemCount;
SCRIPT_LOGATTR* logicalAttributes = scriptParagraph->CharLogicalAttributes;
for (; scriptItem != endScriptItem; scriptItem++)
{
int scriptItemCharPos = scriptItem->iCharPos;
int nextScriptItemCharPos = (scriptItem + 1)->iCharPos;
int scriptItemCharCount = nextScriptItemCharPos - scriptItemCharPos;
char* scriptItemChars = chars + scriptItemCharPos;
int result = NativeMethods.ScriptBreak(scriptItemChars,
scriptItemCharCount,
&scriptItem->a, logicalAttributes);
if (result != 0)
Marshal.ThrowExceptionForHR(result);
logicalAttributes += scriptItemCharCount;
}
}
private static void SplitScriptRuns(ScriptParagraph* scriptParagraph, Run* runs, int runCount, SCRIPT_ITEM* scriptItems, int scriptItemCount)
{
// Reserve space for the largest possible number of script runs.
int maxScriptRuns = runCount + scriptItemCount;
scriptParagraph->EnsureScriptRunCapacity(maxScriptRuns);
// Merge Runs and SCRIPT_ITEMs to create ScriptRuns.
Run* run = runs;
int runStartCharIndex = 0;
Run* endRun = runs + runCount;
SCRIPT_ITEM* item = scriptItems;
SCRIPT_ITEM* endItem = scriptItems + scriptItemCount;
ScriptRun* startScriptRun = scriptParagraph->ScriptRuns;
ScriptRun* scriptRun = startScriptRun;
int currentCharIndex = 0;
for (; ; scriptRun++)
{
int runEndCharIndex = runStartCharIndex + run->CharCount;
int itemEndCharIndex = (item + 1)->iCharPos;
if (itemEndCharIndex < runEndCharIndex)
{
scriptRun->Initialize(run, &item->a, currentCharIndex, itemEndCharIndex - currentCharIndex);
currentCharIndex = itemEndCharIndex;
item++;
}
else if (runEndCharIndex < itemEndCharIndex)
{
scriptRun->Initialize(run, &item->a, currentCharIndex, runEndCharIndex - currentCharIndex);
runStartCharIndex = currentCharIndex = runEndCharIndex;
run++;
}
else
{
scriptRun->Initialize(run, &item->a, currentCharIndex, runEndCharIndex - currentCharIndex);
runStartCharIndex = currentCharIndex = runEndCharIndex;
run++;
item++;
// All sequences of Runs and Items should always end on the same char so we only
// need to check for termination here.
if (run == endRun)
{
Debug.Assert(item == endItem, "Inconsistent Run and SCRIPT_ITEM sequences.");
break;
}
}
}
scriptParagraph->ScriptRunCount = (int)(scriptRun - startScriptRun) + 1;
}
private static void ScriptItemize(char* chars, int charCount, bool rightToLeft,
UnmanagedBuffer tempScriptItemBuffer, out SCRIPT_ITEM* scriptItems, out int scriptItemCount)
{
var scriptControl = new SCRIPT_CONTROL();
var scriptState = new SCRIPT_STATE();
if (rightToLeft)
{
// Start in a RTL context.
scriptState.uBidiLevel = 1;
}
for (; ; )
{
scriptItems = (SCRIPT_ITEM*)tempScriptItemBuffer.GetPointer();
int result = NativeMethods.ScriptItemize(chars, charCount,
tempScriptItemBuffer.Capacity - 1 /*itemize needs 1 extra item beyond capacity as a sentinel*/,
&scriptControl, &scriptState, scriptItems, out scriptItemCount);
if (result == NativeConstants.S_OK)
return;
if (result != NativeConstants.E_OUTOFMEMORY)
Marshal.ThrowExceptionForHR(result);
tempScriptItemBuffer.SetCapacity(tempScriptItemBuffer.Capacity * 2);
}
}