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Implemented metrics on Windows and fixed Unicode conversion in uiDrawNewTextLayout().

This commit is contained in:
Pietro Gagliardi 2016-01-13 00:54:52 -05:00
parent 776be61c45
commit 454fabaf2b
1 changed files with 29 additions and 15 deletions
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44
windows/drawtext.cpp
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@ -108,19 +108,6 @@ void uiDrawFreeFontFamilies(uiDrawFontFamilies *ff)
uiFree(ff); uiFree(ff);
} }
// text sizes are 1/72 of an inch
// points in Direct2D are 1/96 of an inch (https://msdn.microsoft.com/en-us/library/windows/desktop/ff684173%28v=vs.85%29.aspx, https://msdn.microsoft.com/en-us/library/windows/desktop/hh447022%28v=vs.85%29.aspx)
// the first link above has an example conversion; that seems to confirm that these two functions are right (TODO)
double uiDrawTextSizeToPoints(double textSize)
{
return textSize * (96.0 / 72.0);
}
double uiDrawPointsToTextSize(double points)
{
return points * (72.0 / 96.0);
}
struct uiDrawTextFont { struct uiDrawTextFont {
IDWriteFont *f; IDWriteFont *f;
WCHAR *family; // save for convenience in uiDrawNewTextLayout() WCHAR *family; // save for convenience in uiDrawNewTextLayout()
@ -282,6 +269,32 @@ void uiDrawTextFontDescribe(uiDrawTextFont *font, uiDrawTextFontDescriptor *desc
// TODO // TODO
} }
// text sizes are 1/72 of an inch
// points in Direct2D are 1/96 of an inch (https://msdn.microsoft.com/en-us/library/windows/desktop/ff684173%28v=vs.85%29.aspx, https://msdn.microsoft.com/en-us/library/windows/desktop/hh447022%28v=vs.85%29.aspx)
// As for the actual conversion from design units, see:
// - http://cboard.cprogramming.com/windows-programming/136733-directwrite-font-height-issues.html
// - https://sourceforge.net/p/vstgui/mailman/message/32483143/
// - http://xboxforums.create.msdn.com/forums/t/109445.aspx
// - https://msdn.microsoft.com/en-us/library/dd183564%28v=vs.85%29.aspx
// - http://www.fontbureau.com/blog/the-em/
static double scaleUnits(double what, double designUnitsPerEm, double size)
{
return (what / designUnitsPerEm) * (size * (96.0 / 72.0));
}
void uiDrawTextFontGetMetrics(uiDrawTextFont *font, uiDrawTextFontMetrics *metrics)
{
DWRITE_FONT_METRICS dm;
font->f->GetMetrics(&dm);
metrics->Ascent = scaleUnits(dm.ascent, dm.designUnitsPerEm, font->size);
metrics->Descent = scaleUnits(dm.descent, dm.designUnitsPerEm, font->size);
// TODO what happens if dm.xxx is negative?
metrics->Leading = scaleUnits(dm.lineGap, dm.designUnitsPerEm, font->size);
metrics->UnderlinePos = scaleUnits(dm.underlinePosition, dm.designUnitsPerEm, font->size);
metrics->UnderlineThickness = scaleUnits(dm.underlineThickness, dm.designUnitsPerEm, font->size);
}
struct uiDrawTextLayout { struct uiDrawTextLayout {
IDWriteTextFormat *format; IDWriteTextFormat *format;
IDWriteTextLayout *layout; IDWriteTextLayout *layout;
@ -289,6 +302,7 @@ struct uiDrawTextLayout {
}; };
#define MBTWC(str, n, wstr, bufsiz) MultiByteToWideChar(CP_UTF8, 0, str, n, wstr, bufsiz) #define MBTWC(str, n, wstr, bufsiz) MultiByteToWideChar(CP_UTF8, 0, str, n, wstr, bufsiz)
#define MBTWCErr(str, n, wstr, bufsiz) MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, str, n, wstr, bufsiz)
// TODO figure out how ranges are specified in DirectWrite // TODO figure out how ranges are specified in DirectWrite
// TODO clean up the local variable names and improve documentation // TODO clean up the local variable names and improve documentation
@ -319,8 +333,8 @@ static intmax_t *toUTF16Offsets(const char *str, WCHAR **wstr, intmax_t *wlenout
// figure out how many characters to convert and convert them // figure out how many characters to convert and convert them
found = FALSE; found = FALSE;
for (n = 1; (i + n - 1) < len; n++) { for (n = 1; (i + n - 1) < len; n++) {
// TODO do we need MB_ERR_INVALID_CHARS here for this to work properly? // we need MB_ERR_INVALID_CHARS here for this to work properly
m = MBTWC(str + i, n, *wstr + outpos, wlen - outpos); m = MBTWCErr(str + i, n, *wstr + outpos, wlen - outpos);
if (m != 0) { // found a full character if (m != 0) { // found a full character
found = TRUE; found = TRUE;
break; break;