epoger@google.com | ec3ed6a | 2011-07-28 14:26:00 +0000 | [diff] [blame^] | 1 | |
| 2 | /* |
| 3 | * Copyright 2006 The Android Open Source Project |
| 4 | * |
| 5 | * Use of this source code is governed by a BSD-style license that can be |
| 6 | * found in the LICENSE file. |
| 7 | */ |
| 8 | |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 9 | |
| 10 | #include "SkTextBox.h" |
reed@android.com | f2b98d6 | 2010-12-20 18:26:13 +0000 | [diff] [blame] | 11 | #include "../core/SkGlyphCache.h" |
reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame] | 12 | #include "SkUtils.h" |
| 13 | #include "SkAutoKern.h" |
| 14 | |
| 15 | static inline int is_ws(int c) |
| 16 | { |
| 17 | return !((c - 1) >> 5); |
| 18 | } |
| 19 | |
| 20 | static size_t linebreak(const char text[], const char stop[], const SkPaint& paint, SkScalar margin) |
| 21 | { |
| 22 | const char* start = text; |
| 23 | |
| 24 | SkAutoGlyphCache ac(paint, NULL); |
| 25 | SkGlyphCache* cache = ac.getCache(); |
| 26 | SkFixed w = 0; |
| 27 | SkFixed limit = SkScalarToFixed(margin); |
| 28 | SkAutoKern autokern; |
| 29 | |
| 30 | const char* word_start = text; |
| 31 | int prevWS = true; |
| 32 | |
| 33 | while (text < stop) |
| 34 | { |
| 35 | const char* prevText = text; |
| 36 | SkUnichar uni = SkUTF8_NextUnichar(&text); |
| 37 | int currWS = is_ws(uni); |
| 38 | const SkGlyph& glyph = cache->getUnicharMetrics(uni); |
| 39 | |
| 40 | if (!currWS && prevWS) |
| 41 | word_start = prevText; |
| 42 | prevWS = currWS; |
| 43 | |
| 44 | w += autokern.adjust(glyph) + glyph.fAdvanceX; |
| 45 | if (w > limit) |
| 46 | { |
| 47 | if (currWS) // eat the rest of the whitespace |
| 48 | { |
| 49 | while (text < stop && is_ws(SkUTF8_ToUnichar(text))) |
| 50 | text += SkUTF8_CountUTF8Bytes(text); |
| 51 | } |
| 52 | else // backup until a whitespace (or 1 char) |
| 53 | { |
| 54 | if (word_start == start) |
| 55 | { |
| 56 | if (prevText > start) |
| 57 | text = prevText; |
| 58 | } |
| 59 | else |
| 60 | text = word_start; |
| 61 | } |
| 62 | break; |
| 63 | } |
| 64 | } |
| 65 | return text - start; |
| 66 | } |
| 67 | |
| 68 | int SkTextLineBreaker::CountLines(const char text[], size_t len, const SkPaint& paint, SkScalar width) |
| 69 | { |
| 70 | const char* stop = text + len; |
| 71 | int count = 0; |
| 72 | |
| 73 | if (width > 0) |
| 74 | { |
| 75 | do { |
| 76 | count += 1; |
| 77 | text += linebreak(text, stop, paint, width); |
| 78 | } while (text < stop); |
| 79 | } |
| 80 | return count; |
| 81 | } |
| 82 | |
| 83 | ////////////////////////////////////////////////////////////////////////////// |
| 84 | |
| 85 | SkTextBox::SkTextBox() |
| 86 | { |
| 87 | fBox.setEmpty(); |
| 88 | fSpacingMul = SK_Scalar1; |
| 89 | fSpacingAdd = 0; |
| 90 | fMode = kLineBreak_Mode; |
| 91 | fSpacingAlign = kStart_SpacingAlign; |
| 92 | } |
| 93 | |
| 94 | void SkTextBox::setMode(Mode mode) |
| 95 | { |
| 96 | SkASSERT((unsigned)mode < kModeCount); |
| 97 | fMode = SkToU8(mode); |
| 98 | } |
| 99 | |
| 100 | void SkTextBox::setSpacingAlign(SpacingAlign align) |
| 101 | { |
| 102 | SkASSERT((unsigned)align < kSpacingAlignCount); |
| 103 | fSpacingAlign = SkToU8(align); |
| 104 | } |
| 105 | |
| 106 | void SkTextBox::getBox(SkRect* box) const |
| 107 | { |
| 108 | if (box) |
| 109 | *box = fBox; |
| 110 | } |
| 111 | |
| 112 | void SkTextBox::setBox(const SkRect& box) |
| 113 | { |
| 114 | fBox = box; |
| 115 | } |
| 116 | |
| 117 | void SkTextBox::setBox(SkScalar left, SkScalar top, SkScalar right, SkScalar bottom) |
| 118 | { |
| 119 | fBox.set(left, top, right, bottom); |
| 120 | } |
| 121 | |
| 122 | void SkTextBox::getSpacing(SkScalar* mul, SkScalar* add) const |
| 123 | { |
| 124 | if (mul) |
| 125 | *mul = fSpacingMul; |
| 126 | if (add) |
| 127 | *add = fSpacingAdd; |
| 128 | } |
| 129 | |
| 130 | void SkTextBox::setSpacing(SkScalar mul, SkScalar add) |
| 131 | { |
| 132 | fSpacingMul = mul; |
| 133 | fSpacingAdd = add; |
| 134 | } |
| 135 | |
| 136 | ///////////////////////////////////////////////////////////////////////////////////////////// |
| 137 | |
| 138 | void SkTextBox::draw(SkCanvas* canvas, const char text[], size_t len, const SkPaint& paint) |
| 139 | { |
| 140 | SkASSERT(canvas && &paint && (text || len == 0)); |
| 141 | |
| 142 | SkScalar marginWidth = fBox.width(); |
| 143 | |
| 144 | if (marginWidth <= 0 || len == 0) |
| 145 | return; |
| 146 | |
| 147 | const char* textStop = text + len; |
| 148 | |
| 149 | SkScalar x, y, scaledSpacing, height, fontHeight; |
| 150 | SkPaint::FontMetrics metrics; |
| 151 | |
| 152 | switch (paint.getTextAlign()) { |
| 153 | case SkPaint::kLeft_Align: |
| 154 | x = 0; |
| 155 | break; |
| 156 | case SkPaint::kCenter_Align: |
| 157 | x = SkScalarHalf(marginWidth); |
| 158 | break; |
| 159 | default: |
| 160 | x = marginWidth; |
| 161 | break; |
| 162 | } |
| 163 | x += fBox.fLeft; |
| 164 | |
| 165 | fontHeight = paint.getFontMetrics(&metrics); |
| 166 | scaledSpacing = SkScalarMul(fontHeight, fSpacingMul) + fSpacingAdd; |
| 167 | height = fBox.height(); |
| 168 | |
| 169 | // compute Y position for first line |
| 170 | { |
| 171 | SkScalar textHeight = fontHeight; |
| 172 | |
| 173 | if (fMode == kLineBreak_Mode && fSpacingAlign != kStart_SpacingAlign) |
| 174 | { |
| 175 | int count = SkTextLineBreaker::CountLines(text, textStop - text, paint, marginWidth); |
| 176 | SkASSERT(count > 0); |
| 177 | textHeight += scaledSpacing * (count - 1); |
| 178 | } |
| 179 | |
| 180 | switch (fSpacingAlign) { |
| 181 | case kStart_SpacingAlign: |
| 182 | y = 0; |
| 183 | break; |
| 184 | case kCenter_SpacingAlign: |
| 185 | y = SkScalarHalf(height - textHeight); |
| 186 | break; |
| 187 | default: |
| 188 | SkASSERT(fSpacingAlign == kEnd_SpacingAlign); |
| 189 | y = height - textHeight; |
| 190 | break; |
| 191 | } |
| 192 | y += fBox.fTop - metrics.fAscent; |
| 193 | } |
| 194 | |
| 195 | for (;;) |
| 196 | { |
| 197 | len = linebreak(text, textStop, paint, marginWidth); |
| 198 | if (y + metrics.fDescent + metrics.fLeading > 0) |
| 199 | canvas->drawText(text, len, x, y, paint); |
| 200 | text += len; |
| 201 | if (text >= textStop) |
| 202 | break; |
| 203 | y += scaledSpacing; |
| 204 | if (y + metrics.fAscent >= height) |
| 205 | break; |
| 206 | } |
| 207 | } |
| 208 | |
reed@android.com | 033e03c | 2010-05-18 21:17:43 +0000 | [diff] [blame] | 209 | /////////////////////////////////////////////////////////////////////////////// |
| 210 | |
| 211 | void SkTextBox::setText(const char text[], size_t len, const SkPaint& paint) { |
| 212 | fText = text; |
| 213 | fLen = len; |
| 214 | fPaint = &paint; |
| 215 | } |
| 216 | |
| 217 | void SkTextBox::draw(SkCanvas* canvas) { |
| 218 | this->draw(canvas, fText, fLen, *fPaint); |
| 219 | } |
| 220 | |
| 221 | int SkTextBox::countLines() const { |
| 222 | return SkTextLineBreaker::CountLines(fText, fLen, *fPaint, fBox.width()); |
| 223 | } |
| 224 | |
| 225 | SkScalar SkTextBox::getTextHeight() const { |
| 226 | SkScalar spacing = SkScalarMul(fPaint->getTextSize(), fSpacingMul) + fSpacingAdd; |
| 227 | return this->countLines() * spacing; |
| 228 | } |
| 229 | |