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libui/windows/drawtext.cpp

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// 17 january 2017
#include "uipriv_windows.hpp"
#include "draw.hpp"
// TODO
// - consider the warnings about antialiasing in the PadWrite sample
// - if that's not a problem, do we have overlapping rects in the hittest sample? I can't tell...
// - what happens if any nLines == 0?
struct uiDrawTextLayout {
IDWriteTextFormat *format;
IDWriteTextLayout *layout;
UINT32 nLines;
struct lineInfo *lineInfo;
// for converting DirectWrite indices from/to byte offsets
size_t *u8tou16;
size_t nUTF8;
size_t *u16tou8;
size_t nUTF16;
};
// TODO copy notes about DirectWrite DIPs being equal to Direct2D DIPs here
// typographic points are 1/72 inch; this parameter is 1/96 inch
// fortunately Microsoft does this too, in https://msdn.microsoft.com/en-us/library/windows/desktop/dd371554%28v=vs.85%29.aspx
#define pointSizeToDWriteSize(size) (size * (96.0 / 72.0))
// TODO should be const but then I can't operator[] on it; the real solution is to find a way to do designated array initializers in C++11 but I do not know enough C++ voodoo to make it work (it is possible but no one else has actually done it before)
static std::map<uiDrawTextItalic, DWRITE_FONT_STYLE> dwriteItalics = {
{ uiDrawTextItalicNormal, DWRITE_FONT_STYLE_NORMAL },
{ uiDrawTextItalicOblique, DWRITE_FONT_STYLE_OBLIQUE },
{ uiDrawTextItalicItalic, DWRITE_FONT_STYLE_ITALIC },
};
// TODO should be const but then I can't operator[] on it; the real solution is to find a way to do designated array initializers in C++11 but I do not know enough C++ voodoo to make it work (it is possible but no one else has actually done it before)
static std::map<uiDrawTextStretch, DWRITE_FONT_STRETCH> dwriteStretches = {
{ uiDrawTextStretchUltraCondensed, DWRITE_FONT_STRETCH_ULTRA_CONDENSED },
{ uiDrawTextStretchExtraCondensed, DWRITE_FONT_STRETCH_EXTRA_CONDENSED },
{ uiDrawTextStretchCondensed, DWRITE_FONT_STRETCH_CONDENSED },
{ uiDrawTextStretchSemiCondensed, DWRITE_FONT_STRETCH_SEMI_CONDENSED },
{ uiDrawTextStretchNormal, DWRITE_FONT_STRETCH_NORMAL },
{ uiDrawTextStretchSemiExpanded, DWRITE_FONT_STRETCH_SEMI_EXPANDED },
{ uiDrawTextStretchExpanded, DWRITE_FONT_STRETCH_EXPANDED },
{ uiDrawTextStretchExtraExpanded, DWRITE_FONT_STRETCH_EXTRA_EXPANDED },
{ uiDrawTextStretchUltraExpanded, DWRITE_FONT_STRETCH_ULTRA_EXPANDED },
};
struct lineInfo {
size_t startPos; // in UTF-16 points
size_t endPos;
size_t newlineCount;
double x;
double y;
double width;
double height;
double baseline;
};
// this function is deeply indebted to the PadWrite sample: https://github.com/Microsoft/Windows-classic-samples/blob/master/Samples/Win7Samples/multimedia/DirectWrite/PadWrite/TextEditor.cpp
static void computeLineInfo(uiDrawTextLayout *tl)
{
DWRITE_LINE_METRICS *dlm;
size_t nextStart;
UINT32 i, j;
DWRITE_HIT_TEST_METRICS *htm;
UINT32 nFragments, unused;
HRESULT hr;
// TODO make sure this is legal; if not, switch to GetMetrics() and use its line count field instead
hr = tl->layout->GetLineMetrics(NULL, 0, &(tl->nLines));
// ugh, HRESULT_TO_WIN32() is an inline function and is not constexpr so we can't use switch here
if (hr == S_OK) {
// TODO what do we do here
} else if (hr != E_NOT_SUFFICIENT_BUFFER)
logHRESULT(L"error getting number of lines in IDWriteTextLayout", hr);
tl->lineInfo = (struct lineInfo *) uiAlloc(tl->nLines * sizeof (struct lineInfo), "struct lineInfo[] (text layout)");
dlm = new DWRITE_LINE_METRICS[tl->nLines];
// we can't pass NULL here; it outright crashes if we do
// TODO verify the numbers haven't changed
hr = tl->layout->GetLineMetrics(dlm, tl->nLines, &unused);
if (hr != S_OK)
logHRESULT(L"error getting IDWriteTextLayout line metrics", hr);
// assume the first line starts at position 0 and the string flow is incremental
nextStart = 0;
for (i = 0; i < tl->nLines; i++) {
tl->lineInfo[i].startPos = nextStart;
tl->lineInfo[i].endPos = nextStart + dlm[i].length;
tl->lineInfo[i].newlineCount = dlm[i].newlineLength;
nextStart = tl->lineInfo[i].endPos;
// a line can have multiple fragments; for example, if there's a bidirectional override in the middle of a line
hr = tl->layout->HitTestTextRange(tl->lineInfo[i].startPos, (tl->lineInfo[i].endPos - tl->lineInfo[i].newlineCount) - tl->lineInfo[i].startPos,
0, 0,
NULL, 0, &nFragments);
if (hr != S_OK && hr != E_NOT_SUFFICIENT_BUFFER)
logHRESULT(L"error getting IDWriteTextLayout line fragment count", hr);
htm = new DWRITE_HIT_TEST_METRICS[nFragments];
// TODO verify unused == nFragments?
hr = tl->layout->HitTestTextRange(tl->lineInfo[i].startPos, (tl->lineInfo[i].endPos - tl->lineInfo[i].newlineCount) - tl->lineInfo[i].startPos,
0, 0,
htm, nFragments, &unused);
// TODO can this return E_NOT_SUFFICIENT_BUFFER again?
if (hr != S_OK)
logHRESULT(L"error getting IDWriteTextLayout line fragment metrics", hr);
// TODO verify htm.textPosition and htm.length against dtm[i]/tl->lineInfo[i]?
tl->lineInfo[i].x = htm[0].left;
tl->lineInfo[i].y = htm[0].top;
// TODO does this not include trailing whitespace? I forget
tl->lineInfo[i].width = htm[0].width;
tl->lineInfo[i].height = htm[0].height;
for (j = 1; j < nFragments; j++) {
// this is correct even if the leftmost fragment on the line is RTL
if (tl->lineInfo[i].x > htm[j].left)
tl->lineInfo[i].x = htm[j].left;
tl->lineInfo[i].width += htm[j].width;
// TODO verify y and height haven't changed?
}
// TODO verify dlm[i].height == htm.height?
delete[] htm;
// TODO on Windows 8.1 and/or 10 we can use DWRITE_LINE_METRICS1 to get specific info about the ascent and descent; do we have an alternative?
// TODO and even on those platforms can we somehow split tyographic leading from spacing?
// TODO and on that note, can we have both line spacing proportionally above and uniformly below?
tl->lineInfo[i].baseline = dlm[i].baseline;
}
delete[] dlm;
}
// TODO should be const but then I can't operator[] on it; the real solution is to find a way to do designated array initializers in C++11 but I do not know enough C++ voodoo to make it work (it is possible but no one else has actually done it before)
static std::map<uiDrawTextItalic, DWRITE_TEXT_ALIGNMENT> dwriteAligns = {
{ uiDrawTextLayoutAlignLeft, DWRITE_TEXT_ALIGNMENT_LEADING },
{ uiDrawTextLayoutAlignCenter, DWRITE_TEXT_ALIGNMENT_CENTER },
{ uiDrawTextLayoutAlignRight, DWRITE_TEXT_ALIGNMENT_TRAILING },
};
uiDrawTextLayout *uiDrawNewTextLayout(uiDrawTextLayoutParams *p)
{
uiDrawTextLayout *tl;
WCHAR *wDefaultFamily;
DWRITE_WORD_WRAPPING wrap;
FLOAT maxWidth;
HRESULT hr;
tl = uiNew(uiDrawTextLayout);
wDefaultFamily = toUTF16(p->DefaultFont->Family);
hr = dwfactory->CreateTextFormat(
wDefaultFamily, NULL,
// for the most part, DirectWrite weights correlate to ours
// the differences:
// - Minimum — libui: 0, DirectWrite: 1
// - Maximum — libui: 1000, DirectWrite: 999
// TODO figure out what to do about this shorter range (the actual major values are the same (but with different names), so it's just a range issue)
(DWRITE_FONT_WEIGHT) (p->DefaultFont->Weight),
dwriteItalics[p->DefaultFont->Italic],
dwriteStretches[p->DefaultFont->Stretch],
pointSizeToDWriteSize(p->DefaultFont->Size),
// see http://stackoverflow.com/questions/28397971/idwritefactorycreatetextformat-failing and https://msdn.microsoft.com/en-us/library/windows/desktop/dd368203.aspx
// TODO use the current locale?
L"",
&(tl->format));
if (hr != S_OK)
logHRESULT(L"error creating IDWriteTextFormat", hr);
hr = tl->format->SetTextAlignment(dwriteAligns[p->Align]);
if (hr != S_OK)
logHRESULT(L"error applying text layout alignment", hr);
hr = dwfactory->CreateTextLayout(
(const WCHAR *) attrstrUTF16(p->String), attrstrUTF16Len(p->String),
tl->format,
// FLOAT is float, not double, so this should work... TODO
FLT_MAX, FLT_MAX,
&(tl->layout));
if (hr != S_OK)
logHRESULT(L"error creating IDWriteTextLayout", hr);
// and set the width
// this is the only wrapping mode (apart from "no wrap") available prior to Windows 8.1 (TODO verify this fact) (TODO this should be the default anyway)
wrap = DWRITE_WORD_WRAPPING_WRAP;
maxWidth = (FLOAT) (p->Width);
if (p->Width < 0) {
// TODO is this wrapping juggling even necessary?
wrap = DWRITE_WORD_WRAPPING_NO_WRAP;
// setting the max width in this case technically isn't needed since the wrap mode will simply ignore the max width, but let's do it just to be safe
maxWidth = FLT_MAX; // see TODO above
}
hr = tl->layout->SetWordWrapping(wrap);
if (hr != S_OK)
logHRESULT(L"error setting IDWriteTextLayout word wrapping mode", hr);
hr = tl->layout->SetMaxWidth(maxWidth);
if (hr != S_OK)
logHRESULT(L"error setting IDWriteTextLayout max layout width", hr);
computeLineInfo(tl);
// and finally copy the UTF-8/UTF-16 index conversion tables
tl->u8tou16 = attrstrCopyUTF8ToUTF16(p->String, &(tl->nUTF8));
tl->u16tou8 = attrstrCopyUTF16ToUTF8(p->String, &(tl->nUTF16));
// TODO can/should this be moved elsewhere?
uiFree(wDefaultFamily);
return tl;
}
void uiDrawFreeTextLayout(uiDrawTextLayout *tl)
{
uiFree(tl->u16tou8);
uiFree(tl->u8tou16);
uiFree(tl->lineInfo);
tl->layout->Release();
tl->format->Release();
uiFree(tl);
}
static ID2D1SolidColorBrush *mkSolidBrush(ID2D1RenderTarget *rt, double r, double g, double b, double a)
{
D2D1_BRUSH_PROPERTIES props;
D2D1_COLOR_F color;
ID2D1SolidColorBrush *brush;
HRESULT hr;
ZeroMemory(&props, sizeof (D2D1_BRUSH_PROPERTIES));
props.opacity = 1.0;
// identity matrix
props.transform._11 = 1;
props.transform._22 = 1;
color.r = r;
color.g = g;
color.b = b;
color.a = a;
hr = rt->CreateSolidColorBrush(
&color,
&props,
&brush);
if (hr != S_OK)
logHRESULT(L"error creating solid brush", hr);
return brush;
}
// TODO this ignores clipping?
void uiDrawText(uiDrawContext *c, uiDrawTextLayout *tl, double x, double y)
{
D2D1_POINT_2F pt;
ID2D1Brush *black;
// TODO document that fully opaque black is the default text color; figure out whether this is upheld in various scenarios on other platforms
// TODO figure out if this needs to be cleaned out
black = mkSolidBrush(c->rt, 0.0, 0.0, 0.0, 1.0);
pt.x = x;
pt.y = y;
// TODO D2D1_DRAW_TEXT_OPTIONS_NO_SNAP?
// TODO D2D1_DRAW_TEXT_OPTIONS_CLIP?
// TODO when setting 8.1 as minimum (TODO verify), D2D1_DRAW_TEXT_OPTIONS_ENABLE_COLOR_FONT?
// TODO what is our pixel snapping setting related to the OPTIONS enum values?
c->rt->DrawTextLayout(pt, tl->layout, black, D2D1_DRAW_TEXT_OPTIONS_NONE);
black->Release();
}
// TODO for a single line the height includes the leading; should it? TextEdit on OS X always includes the leading and/or paragraph spacing, otherwise Klee won't work...
// TODO width does not include trailing whitespace
void uiDrawTextLayoutExtents(uiDrawTextLayout *tl, double *width, double *height)
{
DWRITE_TEXT_METRICS metrics;
HRESULT hr;
hr = tl->layout->GetMetrics(&metrics);
if (hr != S_OK)
logHRESULT(L"error getting IDWriteTextLayout layout metrics", hr);
*width = metrics.width;
// TODO make sure the behavior of this on empty strings is the same on all platforms (ideally should be 0-width, line height-height; TODO note this in the docs too)
*height = metrics.height;
}
int uiDrawTextLayoutNumLines(uiDrawTextLayout *tl)
{
return tl->nLines;
}
// DirectWrite doesn't provide a direct way to do this, so we have to do this manually
// TODO does that comment still apply here or to the code at the top of this file?
void uiDrawTextLayoutLineByteRange(uiDrawTextLayout *tl, int line, size_t *start, size_t *end)
{
*start = tl->lineInfo[line].startPos;
*start = tl->u16tou8[*start];
*end = tl->lineInfo[line].endPos - tl->lineInfo[line].newlineCount;
*end = tl->u16tou8[*end];
}
void uiDrawTextLayoutLineGetMetrics(uiDrawTextLayout *tl, int line, uiDrawTextLayoutLineMetrics *m)
{
m->X = tl->lineInfo[line].x;
m->Y = tl->lineInfo[line].y;
m->Width = tl->lineInfo[line].width;
m->Height = tl->lineInfo[line].height;
// TODO rename tl->lineInfo[line].baseline to .baselineOffset or something of the sort to make its meaning more clear
m->BaselineY = tl->lineInfo[line].y + tl->lineInfo[line].baseline;
m->Ascent = tl->lineInfo[line].baseline;
m->Descent = tl->lineInfo[line].height - tl->lineInfo[line].baseline;
m->Leading = 0; // TODO
m->ParagraphSpacingBefore = 0; // TODO
m->LineHeightSpace = 0; // TODO
m->LineSpacing = 0; // TODO
m->ParagraphSpacing = 0; // TODO
}
// this algorithm comes from Microsoft's PadWrite sample, following TextEditor::SetSelectionFromPoint()
// TODO go back through all of these and make sure we convert coordinates properly
// TODO same for OS X
void uiDrawTextLayoutHitTest(uiDrawTextLayout *tl, double x, double y, size_t *pos, int *line)
{
DWRITE_HIT_TEST_METRICS m;
BOOL trailing, inside;
size_t p;
UINT32 i;
HRESULT hr;
hr = tl->layout->HitTestPoint(x, y,
&trailing, &inside,
&m);
if (hr != S_OK)
logHRESULT(L"error hit-testing IDWriteTextLayout", hr);
p = m.textPosition;
// on a trailing hit, align to the nearest cluster
if (trailing) {
DWRITE_HIT_TEST_METRICS m2;
FLOAT x, y; // crashes if I skip these :/
hr = tl->layout->HitTestTextPosition(m.textPosition, trailing,
&x, &y, &m2);
if (hr != S_OK)
logHRESULT(L"error aligning trailing hit to nearest cluster", hr);
p = m2.textPosition + m2.length;
}
*pos = tl->u16tou8[p];
for (i = 0; i < tl->nLines; i++) {
double ltop, lbottom;
ltop = tl->lineInfo[i].y;
lbottom = ltop + tl->lineInfo[i].height;
// y will already >= ltop at this point since the past lbottom should == ltop
if (y < lbottom)
break;
}
if (i == tl->nLines)
i--;
*line = i;
}
double uiDrawTextLayoutByteLocationInLine(uiDrawTextLayout *tl, size_t pos, int line)
{
BOOL trailing;
DWRITE_HIT_TEST_METRICS m;
FLOAT x, y;
HRESULT hr;
if (line < 0 || line >= tl->nLines)
return -1;
pos = tl->u8tou16[pos];
// note: >, not >=, because the position at endPos is valid!
if (pos < tl->lineInfo[line].startPos || pos > tl->lineInfo[line].endPos)
return -1;
// this behavior seems correct
// there's also PadWrite's TextEditor::GetCaretRect() but that requires state...
// TODO where does this fail?
trailing = FALSE;
if (pos != 0 && pos != tl->nUTF16 && pos == tl->lineInfo[line].endPos) {
pos--;
trailing = TRUE;
}
hr = tl->layout->HitTestTextPosition(pos, trailing,
&x, &y, &m);
if (hr != S_OK)
logHRESULT(L"error calling IDWriteTextLayout::HitTestTextPosition()", hr);
return x;
}
void caretDrawParams(uiDrawContext *c, double height, struct caretDrawParams *p)
{
DWORD caretWidth;
// there seems to be no defined caret color
// the best I can come up with is "inverts colors underneath" (according to https://msdn.microsoft.com/en-us/library/windows/desktop/ms648397(v=vs.85).aspx) which I have no idea how to do (TODO)
// just return black for now
p->r = 0.0;
p->g = 0.0;
p->b = 0.0;
p->a = 1.0;
if (SystemParametersInfoW(SPI_GETCARETWIDTH, 0, &caretWidth, 0) == 0)
// don't log the failure, fall back gracefully
// the instruction to use this comes from https://msdn.microsoft.com/en-us/library/windows/desktop/ms648399(v=vs.85).aspx
// and we have to assume GetSystemMetrics() always succeeds, so
caretWidth = GetSystemMetrics(SM_CXBORDER);
// TODO make this a function and split it out of areautil.cpp
{
FLOAT dpix, dpiy;
// TODO can we pass NULL for dpiy?
c->rt->GetDpi(&dpix, &dpiy);
// see https://msdn.microsoft.com/en-us/library/windows/desktop/dd756649%28v=vs.85%29.aspx (and others; search "direct2d mouse")
p->width = ((double) (caretWidth * 96)) / dpix;
}
// and there doesn't seem to be this either... (TODO check what PadWrite does?)
p->xoff = 0;
}
// TODO split this and the above related font matching code into a separate file?
void fontdescFromIDWriteFont(IDWriteFont *font, uiDrawFontDescriptor *uidesc)
{
DWRITE_FONT_STYLE dwitalic;
DWRITE_FONT_STRETCH dwstretch;
dwitalic = font->GetStyle();
// TODO reverse the above misalignment if it is corrected
uidesc->Weight = (uiDrawTextWeight) (font->GetWeight());
dwstretch = font->GetStretch();
for (uidesc->Italic = uiDrawTextItalicNormal; uidesc->Italic < uiDrawTextItalicItalic; uidesc->Italic++)
if (dwriteItalics[uidesc->Italic] == dwitalic)
break;
for (uidesc->Stretch = uiDrawTextStretchUltraCondensed; uidesc->Stretch < uiDrawTextStretchUltraExpanded; uidesc->Stretch++)
if (dwriteStretches[uidesc->Stretch] == dwstretch)
break;
}
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