зеркало из https://github.com/mozilla/pjs.git
bug 38387; add optimized GetWidth method to Japanese Windows 95-specific
subclass nsRenderingContextWinA to allow proper layout on Win95-J; a,r=kmcclusk
This commit is contained in:
erik%netscape.com
Родитель
cbfbd753fe
Коммит
d8caf32f9e
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@ -3305,6 +3305,296 @@ FoundFont:
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return NS_ERROR_FAILURE;
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}
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NS_IMETHODIMP
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nsRenderingContextWinA::GetWidth(const PRUnichar *aString,
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PRInt32 aLength,
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PRInt32 aAvailWidth,
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PRInt32* aBreaks,
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PRInt32 aNumBreaks,
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nscoord& aWidth,
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PRInt32& aNumCharsFit,
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PRInt32* aFontID)
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{
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NS_PRECONDITION(aBreaks[aNumBreaks - 1] == aLength, "invalid break array");
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if (nsnull != mFontMetrics) {
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// If we need to back up this state represents the last place we could
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// break. We can use this to avoid remeasuring text
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struct PrevBreakState {
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PRInt32 mBreakIndex;
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nscoord mWidth;
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PrevBreakState() {
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mBreakIndex = -1; // not known (hasn't been computed)
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mWidth = 0;
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}
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};
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PRUnichar* pstr = (PRUnichar *)(const PRUnichar *)aString;
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nsFontMetricsWinA* metrics = (nsFontMetricsWinA*) mFontMetrics;
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nsFontSubset* prevFont = nsnull;
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PrevBreakState prevBreakState;
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// Initialize OUT parameter
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aNumCharsFit = 0;
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// Setup the font and foreground color
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SetupFontAndColor();
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// Iterate each character in the string and determine which font to use
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HFONT selectedFont = mCurrFont;
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nscoord width = 0;
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PRInt32 start = 0;
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PRInt32 i = 0;
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PRBool allDone = PR_FALSE;
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while (!allDone) {
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nsFontSubset* currFont = nsnull;
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nsFontMetricsWinA* fontMetricsWin;
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nscoord aveCharWidth;
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// First search the fonts we already have loaded
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nsFontWinA** font = (nsFontWinA**) metrics->mLoadedFonts;
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nsFontWinA** end = (nsFontWinA**) &metrics->mLoadedFonts[metrics->mLoadedFontsCount];
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while (font < end) {
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if (FONT_HAS_GLYPH((*font)->mMap, pstr[i])) {
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nsFontSubset** subset = (*font)->mSubsets;
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nsFontSubset** endSubsets = &((*font)->mSubsets[(*font)->mSubsetsCount]);
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while (subset < endSubsets) {
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if (!(*subset)->mMap) {
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if (!(*subset)->Load(*font)) {
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subset++;
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continue;
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}
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}
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if (FONT_HAS_GLYPH((*subset)->mMap, pstr[i])) {
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currFont = *subset;
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goto FoundFont;
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}
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subset++;
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}
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}
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font++; // try the next font
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}
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// No match in the already loaded fonts. Find a new font
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currFont = (nsFontSubset*) metrics->FindFont(mDC, pstr[i]);
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FoundFont:
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// See if this is the same font we found for the previous character.
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// If so, then keep accumulating characters
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if (prevFont) {
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if (currFont != prevFont) {
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// The font has changed. We need to measure the existing text using
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// the previous font
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goto MeasureText;
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}
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}
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else {
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prevFont = currFont; // remember this font
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}
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// Advance to the next character
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if (++i >= aLength) {
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allDone = PR_TRUE;
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goto MeasureText; // measure any remaining text
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}
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continue;
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MeasureText:
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// Make sure the font is selected
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if (prevFont->mFont != selectedFont) {
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::SelectObject(mDC, prevFont->mFont);
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selectedFont = prevFont->mFont;
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}
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// Get the average character width
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fontMetricsWin = (nsFontMetricsWinA*)mFontMetrics;
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fontMetricsWin->GetAveCharWidth(aveCharWidth);
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while (start < i) {
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// Estimate how many characters will fit. Do that by diving the available
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// space by the average character width
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PRInt32 estimatedNumChars = (aAvailWidth - width) / aveCharWidth;
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// Make sure the estimated number of characters is at least 1
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if (estimatedNumChars < 1) {
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estimatedNumChars = 1;
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}
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// Find the nearest break offset
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PRInt32 estimatedBreakOffset = start + estimatedNumChars;
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PRInt32 breakIndex = -1; // not computed
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PRBool inMiddleOfSegment = PR_FALSE;
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nscoord numChars;
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// Avoid scanning the break array in the case where we think all
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// the text should fit
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if (i <= estimatedBreakOffset) {
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// Everything should fit
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numChars = i - start;
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} else {
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// Find the nearest place to break that is less than or equal to
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// the estimated break offset
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breakIndex = prevBreakState.mBreakIndex;
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while (aBreaks[breakIndex + 1] <= estimatedBreakOffset) {
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breakIndex++;
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}
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NS_ASSERTION(aBreaks[breakIndex] <= estimatedBreakOffset, "bad break index");
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// We found a place to break that is before the estimated break
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// offset. Where we break depends on whether the text crosses a
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// segment boundary
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if (start < aBreaks[breakIndex]) {
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// The text crosses at least one segment boundary so measure to the
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// break point just before the estimated break offset
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numChars = aBreaks[breakIndex] - start;
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} else {
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// See whether there is another segment boundary between this one
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// and the end of the text
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if ((breakIndex < (aNumBreaks - 1)) && (aBreaks[breakIndex] < i)) {
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breakIndex++;
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numChars = aBreaks[breakIndex] - start;
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} else {
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NS_ASSERTION(i != aBreaks[breakIndex], "don't expect to be at segment boundary");
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// The text is all within the same segment
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numChars = i - start;
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// Remember we're in the middle of a segment and not in between
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// two segments
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inMiddleOfSegment = PR_TRUE;
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}
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}
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}
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// Measure the text
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PRInt32 pxWidth;
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nscoord twWidth;
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if ((1 == numChars) && (pstr[start] == ' ')) {
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fontMetricsWin->GetSpaceWidth(twWidth);
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} else {
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pxWidth = prevFont->GetWidth(mDC, &pstr[start], numChars);
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twWidth = NSToCoordRound(float(pxWidth) * mP2T);
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}
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// See if the text fits
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PRBool textFits = (twWidth + width) <= aAvailWidth;
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// If the text fits then update the width and the number of
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// characters that fit
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if (textFits) {
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aNumCharsFit += numChars;
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width += twWidth;
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// If we computed the break index and we're not in the middle
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// of a segment then this is a spot that we can back up to if
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// we need to so remember this state
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if ((breakIndex != -1) && !inMiddleOfSegment) {
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prevBreakState.mBreakIndex = breakIndex;
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prevBreakState.mWidth = width;
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}
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} else {
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// The text didn't fit. If we're out of room then we're all done
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allDone = PR_TRUE;
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// See if we can just back up to the previous saved state and not
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// have to measure any text
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if (prevBreakState.mBreakIndex != -1) {
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PRBool canBackup;
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// If we're in the middle of a word then the break index
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// must be the same if we can use it. If we're at a segment
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// boundary, then if the saved state is for the previous
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// break index then we can use it
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if (inMiddleOfSegment) {
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canBackup = prevBreakState.mBreakIndex == breakIndex;
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} else {
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canBackup = prevBreakState.mBreakIndex == (breakIndex - 1);
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}
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if (canBackup) {
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aNumCharsFit = aBreaks[prevBreakState.mBreakIndex];
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width = prevBreakState.mWidth;
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break;
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}
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}
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// We can't just revert to the previous break state. Find the break
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// index just before the end of the text
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i = start + numChars;
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if (breakIndex == -1) {
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breakIndex = 0;
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while (aBreaks[breakIndex + 1] < i) {
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breakIndex++;
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}
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}
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if ((0 == breakIndex) && (i <= aBreaks[0])) {
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// There's no place to back up to so even though the text doesn't fit
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// return it anyway
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aNumCharsFit += numChars;
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width += twWidth;
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break;
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}
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// Repeatedly back up until we get to where the text fits or we're
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// all the way back to the first word
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width += twWidth;
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while ((breakIndex >= 0) && (width > aAvailWidth)) {
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start = aBreaks[breakIndex];
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numChars = i - start;
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if ((1 == numChars) && (pstr[start] == ' ')) {
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fontMetricsWin->GetSpaceWidth(twWidth);
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} else {
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pxWidth = prevFont->GetWidth(mDC, &pstr[start], numChars);
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twWidth = NSToCoordRound(float(pxWidth) * mP2T);
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}
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width -= twWidth;
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aNumCharsFit = start;
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breakIndex--;
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i = start;
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}
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}
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start += numChars;
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}
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// We're done measuring that run
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if (!allDone) {
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prevFont = currFont;
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NS_ASSERTION(start == i, "internal error");
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// Advance to the next character
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if (++i >= aLength) {
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allDone = PR_TRUE;
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goto MeasureText;
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}
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}
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}
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aWidth = width;
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if (selectedFont != mCurrFont) {
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// Restore the font
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::SelectObject(mDC, mCurrFont);
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}
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if (nsnull != aFontID) {
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*aFontID = 0;
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}
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return NS_OK;
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}
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return NS_ERROR_FAILURE;
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}
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NS_IMETHODIMP nsRenderingContextWinA :: DrawString(const PRUnichar *aString, PRUint32 aLength,
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nscoord aX, nscoord aY,
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PRInt32 aFontID,
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@ -270,6 +270,14 @@ class nsRenderingContextWinA : public nsRenderingContextWin
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public:
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NS_IMETHOD GetWidth(const PRUnichar* aString, PRUint32 aLength,
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nscoord& aWidth, PRInt32 *aFontID);
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NS_IMETHOD GetWidth(const PRUnichar *aString,
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PRInt32 aLength,
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PRInt32 aAvailWidth,
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PRInt32* aBreaks,
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PRInt32 aNumBreaks,
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nscoord& aWidth,
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PRInt32& aNumCharsFit,
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PRInt32* aFontID);
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NS_IMETHOD DrawString(const PRUnichar *aString, PRUint32 aLength,
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nscoord aX, nscoord aY,
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PRInt32 aFontID,
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