summaryrefslogtreecommitdiffstats
path: root/khtml/rendering/font.cpp
blob: 64ede83e3f2a4783e09231c3fcfd98822ef1624b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
/**
 * This file is part of the html renderer for KDE.
 *
 * Copyright (C) 1999-2003 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 *           (C) 2000 Dirk Mueller (mueller@kde.org)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#include "config.h"

#ifdef HAVE_ALLOCA_H
#include <alloca.h>
#endif

#include "font.h"
#include "khtml_factory.h"
#include "khtml_settings.h"

#include <kdebug.h>
#include <kglobal.h>

#include <tqpainter.h>
#include <tqfontdatabase.h>
#include <tqpaintdevicemetrics.h>

using namespace khtml;

/** closes the current word and returns its width in pixels
 * @param fm metrics of font to be used
 * @param str string
 * @param pos zero-indexed position within @p str upon which all other
 *	indices are based
 * @param wordStart relative index pointing to the position where the word started
 * @param wordEnd relative index pointing one position after the word ended
 * @return the width in pixels. May be 0 if @p wordStart and @p wordEnd were
 *	equal.
 */
inline int closeWordAndGetWidth(const TQFontMetrics &fm, const TQChar *str, int pos,
	int wordStart, int wordEnd)
{
    if (wordEnd <= wordStart) return 0;

    TQConstString s(str + pos + wordStart, wordEnd - wordStart);
    return fm.width(s.string());
}

/** closes the current word and draws it
 * @param p painter
 * @param d text direction
 * @param x current x position, will be inc-/decremented correctly according
 *	to text direction
 * @param y baseline of text
 * @param widths list of widths; width of word is expected at position
 *		wordStart
 * @param str string
 * @param pos zero-indexed position within @p str upon which all other
 *	indices are based
 * @param wordStart relative index pointing to the position where the word started,
 *	will be set to wordEnd after function
 * @param wordEnd relative index pointing one position after the word ended
 */
inline void closeAndDrawWord(TQPainter *p, TQPainter::TextDirection d,
	int &x, int y, const short widths[], const TQChar *str, int pos,
	int &wordStart, int wordEnd)
{
    if (wordEnd <= wordStart) return;

    int width = widths[wordStart];
    if (d == TQPainter::RTL)
      x -= width;

    TQConstString s(str + pos + wordStart, wordEnd - wordStart);
    p->drawText(x, y, s.string(), -1, d);

    if (d != TQPainter::RTL)
      x += width;

    wordStart = wordEnd;
}

void Font::drawText( TQPainter *p, int x, int y, TQChar *str, int slen, int pos, int len,
        int toAdd, TQPainter::TextDirection d, int from, int to, TQColor bg, int uy, int h, int deco ) const
{
    if (!str) return;
    TQConstString cstr = TQConstString(str, slen);
    TQString qstr = cstr.string();

    // ### fixme for RTL
    if ( !scFont && !letterSpacing && !wordSpacing && !toAdd && from==-1 ) {
	// simply draw it
	// Due to some unfounded cause TQPainter::drawText traverses the
        // *whole* string when painting, not only the specified
        // [pos, pos + len) segment. This makes painting *extremely* slow for
        // long render texts (in the order of several megabytes).
        // Hence, only hand over the piece of text of the actual inline text box
	TQConstString cstr = TQConstString(str + pos, len);
	p->drawText( x, y, cstr.string(), 0, len, d );
    } else {
	if (from < 0) from = 0;
	if (to < 0) to = len;

	int numSpaces = 0;
	if ( toAdd ) {
	    for( int i = 0; i < len; ++i )
		if ( str[i+pos].category() == TQChar::Separator_Space )
		    ++numSpaces;
	}

	const int totWidth = width( str, slen, pos, len );
	if ( d == TQPainter::RTL ) {
	    x += totWidth + toAdd;
	}
	TQString upper = qstr;
	TQFontMetrics sc_fm = fm;
	if ( scFont ) {
	    // draw in small caps
	    upper = qstr.upper();
	    sc_fm = TQFontMetrics( *scFont );
	}

	// ### sc could be optimized by only painting uppercase letters extra,
	// and treat the rest WordWise, but I think it's not worth it.
	// Somebody else may volunteer, and implement this ;-) (LS)

	// The mode determines whether the text is displayed character by
	// character, word by word, or as a whole
	enum { CharacterWise, WordWise, Whole }
	mode = Whole;
	if (!letterSpacing && !scFont && (wordSpacing || toAdd > 0))
	  mode = WordWise;
	else if (letterSpacing || scFont)
	  mode = CharacterWise;

	if (mode == Whole) {	// most likely variant is treated extra

	    if (to < 0) to = len;
	    const TQConstString cstr(str + pos, len);
	    const TQConstString segStr(str + pos + from, to - from);
	    const int preSegmentWidth = fm.width(cstr.string(), from);
	    const int segmentWidth = fm.width(segStr.string());
	    const int eff_x = d == TQPainter::RTL ? x - preSegmentWidth - segmentWidth
					: x + preSegmentWidth;

	    // draw whole string segment, with optional background
	    if ( bg.isValid() )
		p->fillRect( eff_x, uy, segmentWidth, h, bg );
	    p->drawText(eff_x, y, segStr.string(), -1, d);
	    if (deco)
	        drawDecoration(p, eff_x, uy, y - uy, segmentWidth - 1, h, deco);
	    return;
	}

	// We are using two passes. In the first pass, the widths are collected,
	// and stored. In the second, the actual characters are drawn.

	// For each letter in the text box, save the width of the character.
	// When word-wise, only the first letter contains the width, but of the
	// whole word.
        short* const widthList = (short *)alloca(to*sizeof(short));

	// First pass: gather widths
	int preSegmentWidth = 0;
	int segmentWidth = 0;
        int lastWordBegin = 0;
	bool onSegment = from == 0;
	for( int i = 0; i < to; ++i ) {
	    if (i == from) {
                // Also close words on visibility boundary
	        if (mode == WordWise) {
	            const int width = closeWordAndGetWidth(fm, str, pos, lastWordBegin, i);

		    if (lastWordBegin < i) {
		        widthList[lastWordBegin] = (short)width;
		        lastWordBegin = i;
		        preSegmentWidth += width;
		    }
		}
		onSegment = true;
	    }

	    const TQChar ch = str[pos+i];
	    bool lowercase = (ch.category() == TQChar::Letter_Lowercase);
	    bool is_space = (ch.category() == TQChar::Separator_Space);
	    int chw = 0;
	    if ( letterSpacing )
		chw += letterSpacing;
	    if ( (wordSpacing || toAdd) && is_space ) {
	        if (mode == WordWise) {
		    const int width = closeWordAndGetWidth(fm, str, pos, lastWordBegin, i);
		    if (lastWordBegin < i) {
		        widthList[lastWordBegin] = (short)width;
			lastWordBegin = i;
		        (onSegment ? segmentWidth : preSegmentWidth) += width;
		    }
		    ++lastWordBegin;		// ignore this space
		}
		chw += wordSpacing;
		if ( numSpaces ) {
		    const int a = toAdd/numSpaces;
		    chw += a;
		    toAdd -= a;
		    --numSpaces;
		}
	    }
	    if (is_space || mode == CharacterWise) {
	        chw += lowercase ? sc_fm.charWidth( upper, pos+i ) : fm.charWidth( qstr, pos+i );
		widthList[i] = (short)chw;

		(onSegment ? segmentWidth : preSegmentWidth) += chw;
	    }

	}

	// close last word
	Q_ASSERT(onSegment);
	if (mode == WordWise) {
	    const int width = closeWordAndGetWidth(fm, str, pos, lastWordBegin, to);
	    segmentWidth += width;
	    widthList[lastWordBegin] = (short)width;
	}

        if (d == TQPainter::RTL) x -= preSegmentWidth;
	else x += preSegmentWidth;

        const int startx = d == TQPainter::RTL ? x-segmentWidth : x;

	// optionally draw background
	if ( bg.isValid() )
	    p->fillRect( startx, uy, segmentWidth, h, bg );

	// second pass: do the actual drawing
        lastWordBegin = from;
	for( int i = from; i < to; ++i ) {
	    const TQChar ch = str[pos+i];
	    bool lowercase = (ch.category() == TQChar::Letter_Lowercase);
	    bool is_space = ch.category() == TQChar::Separator_Space;
	    if ( is_space ) {
	        if (mode == WordWise) {
		    closeAndDrawWord(p, d, x, y, widthList, str, pos, lastWordBegin, i);
		    ++lastWordBegin;	// jump over space
		}
	    }
	    if (is_space || mode == CharacterWise) {
	        const int chw = widthList[i];
	        if (d == TQPainter::RTL)
		    x -= chw;

		if ( scFont )
		    p->setFont( lowercase ? *scFont : f );
		p->drawText( x, y, (lowercase ? upper : qstr), pos+i, 1, d );

	        if (d != TQPainter::RTL)
		    x += chw;
	    }

	}

	// don't forget to draw last word
	if (mode == WordWise) {
	    closeAndDrawWord(p, d, x, y, widthList, str, pos, lastWordBegin, to);
	}

	if (deco)
	    drawDecoration(p, startx, uy, y - uy, segmentWidth - 1, h, deco);

	if ( scFont )
	    p->setFont( f );
    }
}


int Font::width( TQChar *chs, int, int pos, int len, int start, int end, int toAdd ) const
{
    const TQConstString cstr(chs+pos, len);
    int w = 0;

    const TQString qstr = cstr.string();
    if ( scFont ) {
	const TQString upper = qstr.upper();
	const TQChar *uc = qstr.tqunicode();
	const TQFontMetrics sc_fm( *scFont );
	for ( int i = 0; i < len; ++i ) {
	    if ( (uc+i)->category() == TQChar::Letter_Lowercase )
		w += sc_fm.charWidth( upper, i );
	    else
		w += fm.charWidth( qstr, i );
	}
    } else {
	// ### might be a little inaccurate
	w = fm.width( qstr );
    }

    if ( letterSpacing )
	w += len*letterSpacing;

    if ( wordSpacing )
	// add amount
	for( int i = 0; i < len; ++i ) {
	    if( chs[i+pos].category() == TQChar::Separator_Space )
		w += wordSpacing;
	}

    if ( toAdd ) {
        // first gather count of spaces
        int numSpaces = 0;
        for( int i = start; i != end; ++i )
            if ( chs[i].category() == TQChar::Separator_Space )
                ++numSpaces;
        // distribute pixels evenly among spaces, but count only those within
        // [pos, pos+len)
        for ( int i = start; numSpaces && i != pos + len; i++ )
            if ( chs[i].category() == TQChar::Separator_Space ) {
                const int a = toAdd/numSpaces;
                if ( i >= pos ) w += a;
                toAdd -= a;
                --numSpaces;
            }
    }

    return w;
}

int Font::width( TQChar *chs, int slen, int pos ) const
{
    int w;
	if ( scFont && chs[pos].category() == TQChar::Letter_Lowercase ) {
	    TQString str( chs, slen );
	    str[pos] = chs[pos].upper();
	    w = TQFontMetrics( *scFont ).charWidth( str, pos );
	} else {
	    const TQConstString cstr( chs, slen );
	    w = fm.charWidth( cstr.string(), pos );
	}
    if ( letterSpacing )
	w += letterSpacing;

    if ( wordSpacing && (chs+pos)->category() == TQChar::Separator_Space )
		w += wordSpacing;
    return w;
}

/** Querying QFontDB whether something is scalable is expensive, so we cache. */
struct Font::ScalKey 
{
    TQString family;
    int     weight;
    int     italic;

    ScalKey(const TQFont& font) : 
            family(font.family()), weight(font.weight()), italic(font.italic())
    {}

    ScalKey() {}

    bool operator<(const ScalKey& other) const {
        if (weight < other.weight)
            return true;
        if (weight > other.weight)
            return false;

        if (italic < other.italic)
            return true;
        if (italic > other.italic)
            return false;

        return family < other.family;
    }

    bool operator==(const ScalKey& other) const {
        return (weight == other.weight &&
                italic == other.italic && 
                family == other.family);
    }
};

TQMap<Font::ScalKey, Font::ScalInfo>*   Font::scalCache;
TQMap<Font::ScalKey, TQValueList<int> >* Font::scalSizesCache;

bool Font::isFontScalable(TQFontDatabase& db, const TQFont& font) 
{
    if (!scalCache)
        scalCache = new TQMap<ScalKey, ScalInfo>;

    ScalKey key(font);

    ScalInfo &s = (*scalCache)[key];
    if (s == Unknown) {
        s = db.isSmoothlyScalable(font.family(), db.styleString(font)) ? Yes : No;

        if (s == No) {
            /* Cache size info */
            if (!scalSizesCache)
                scalSizesCache = new TQMap<ScalKey, TQValueList<int> >;
            (*scalSizesCache)[key] = db.smoothSizes(font.family(), db.styleString(font));
        }
    }

    return (s == Yes);
}


void Font::update( TQPaintDeviceMetrics* devMetrics ) const
{
    f.setFamily( fontDef.family.isEmpty() ? KHTMLFactory::defaultHTMLSettings()->stdFontName() : fontDef.family );
    f.setItalic( fontDef.italic );
    f.setWeight( fontDef.weight );

    TQFontDatabase db;

    int size = fontDef.size;
    const int lDpiY = kMax(devMetrics->logicalDpiY(), 96);

    // ok, now some magic to get a nice unscaled font
    // all other font properties should be set before this one!!!!
    if( !isFontScalable(db, f) )
    {
        const TQValueList<int>& pointSizes = (*scalSizesCache)[ScalKey(f)];
        // lets see if we find a nice looking font, which is not too far away
        // from the requested one.
        // kdDebug(6080) << "khtml::setFontSize family = " << f.family() << " size requested=" << size << endl;


        float diff = 1; // ### 100% deviation
        float bestSize = 0;

        TQValueList<int>::ConstIterator it = pointSizes.begin();
        const TQValueList<int>::ConstIterator itEnd = pointSizes.end();

        for( ; it != itEnd; ++it )
        {
            float newDiff = ((*it)*(lDpiY/72.) - float(size))/float(size);
            //kdDebug( 6080 ) << "smooth font size: " << *it << " diff=" << newDiff << endl;
            if(newDiff < 0) newDiff = -newDiff;
            if(newDiff < diff)
            {
                diff = newDiff;
                bestSize = *it;
            }
        }
        //kdDebug( 6080 ) << "best smooth font size: " << bestSize << " diff=" << diff << endl;
        if ( bestSize != 0 && diff < 0.2 ) // 20% deviation, otherwise we use a scaled font...
            size = (int)((bestSize*lDpiY) / 72);
    }

    // make sure we don't bust up X11
    // Also, Qt does not support sizing a TQFont to zero.
    size = kMax(1, kMin(255, size));

//       qDebug("setting font to %s, italic=%d, weight=%d, size=%d", fontDef.family.latin1(), fontDef.italic,
//    	   fontDef.weight, size );


    f.setPixelSize( size );

    fm = TQFontMetrics( f );

    // small caps
    delete scFont;
    scFont = 0;

    if ( fontDef.smallCaps ) {
	scFont = new TQFont( f );
	scFont->setPixelSize( kMax(1, f.pixelSize()*7/10) );
    }
}

void Font::drawDecoration(TQPainter *pt, int _tx, int _ty, int baseline, int width, int height, int deco) const
{
    Q_UNUSED(height);
    // thick lines on small fonts look ugly
    const int thickness = fm.height() > 20 ? fm.lineWidth() : 1;
    const TQBrush brush = pt->pen().color();
    if (deco & UNDERLINE) {
        int underlineOffset = ( fm.height() + baseline ) / 2;
        if (underlineOffset <= baseline) underlineOffset = baseline+1;

        pt->fillRect(_tx, _ty + underlineOffset, width + 1, thickness, brush );
    }
    if (deco & OVERLINE) {
        pt->fillRect(_tx, _ty, width + 1, thickness, brush );
    }
    if (deco & LINE_THROUGH) {
        pt->fillRect(_tx, _ty + 2*baseline/3, width + 1, thickness, brush );
    }
}