grab from latest android

git-svn-id: http://skia.googlecode.com/svn/trunk@27 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 216 insertions, 0 deletions

diff --git a/src/views/SkTextBox.cpp b/src/views/SkTextBox.cpp
new file mode 100644
index 0000000000..657f64805c
--- /dev/null
+++ b/src/views/SkTextBox.cpp
@@ -0,0 +1,216 @@
+/* libs/graphics/views/SkTextBox.cpp
+**
+** Copyright 2006, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License"); 
+** you may not use this file except in compliance with the License. 
+** You may obtain a copy of the License at 
+**
+**     http://www.apache.org/licenses/LICENSE-2.0 
+**
+** Unless required by applicable law or agreed to in writing, software 
+** distributed under the License is distributed on an "AS IS" BASIS, 
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+** See the License for the specific language governing permissions and 
+** limitations under the License.
+*/
+
+#include "SkTextBox.h"
+#include "SkGlyphCache.h"
+#include "SkUtils.h"
+#include "SkAutoKern.h"
+
+static inline int is_ws(int c)
+{
+    return !((c - 1) >> 5);
+}
+
+static size_t linebreak(const char text[], const char stop[], const SkPaint& paint, SkScalar margin)
+{
+    const char* start = text;
+
+    SkAutoGlyphCache    ac(paint, NULL);
+    SkGlyphCache*       cache = ac.getCache();
+    SkFixed             w = 0;
+    SkFixed             limit = SkScalarToFixed(margin);
+    SkAutoKern          autokern;
+
+    const char* word_start = text;
+    int         prevWS = true;
+
+    while (text < stop)
+    {
+        const char* prevText = text;
+        SkUnichar   uni = SkUTF8_NextUnichar(&text);
+        int         currWS = is_ws(uni);
+        const SkGlyph&  glyph = cache->getUnicharMetrics(uni);
+
+        if (!currWS && prevWS)
+            word_start = prevText;
+        prevWS = currWS;
+
+        w += autokern.adjust(glyph) + glyph.fAdvanceX;
+        if (w > limit)
+        {
+            if (currWS) // eat the rest of the whitespace
+            {
+                while (text < stop && is_ws(SkUTF8_ToUnichar(text)))
+                    text += SkUTF8_CountUTF8Bytes(text);
+            }
+            else    // backup until a whitespace (or 1 char)
+            {
+                if (word_start == start)
+                {
+                    if (prevText > start)
+                        text = prevText;
+                }
+                else
+                    text = word_start;
+            }
+            break;
+        }
+    }
+    return text - start;
+}
+
+int SkTextLineBreaker::CountLines(const char text[], size_t len, const SkPaint& paint, SkScalar width)
+{
+    const char* stop = text + len;
+    int         count = 0;
+
+    if (width > 0)
+    {
+        do {
+            count += 1;
+            text += linebreak(text, stop, paint, width);
+        } while (text < stop);
+    }
+    return count;
+}
+
+//////////////////////////////////////////////////////////////////////////////
+
+SkTextBox::SkTextBox()
+{
+    fBox.setEmpty();
+    fSpacingMul = SK_Scalar1;
+    fSpacingAdd = 0;
+    fMode = kLineBreak_Mode;
+    fSpacingAlign = kStart_SpacingAlign;
+}
+
+void SkTextBox::setMode(Mode mode)
+{
+    SkASSERT((unsigned)mode < kModeCount);
+    fMode = SkToU8(mode);
+}
+
+void SkTextBox::setSpacingAlign(SpacingAlign align)
+{
+    SkASSERT((unsigned)align < kSpacingAlignCount);
+    fSpacingAlign = SkToU8(align);
+}
+
+void SkTextBox::getBox(SkRect* box) const
+{
+    if (box)
+        *box = fBox;
+}
+
+void SkTextBox::setBox(const SkRect& box)
+{
+    fBox = box;
+}
+
+void SkTextBox::setBox(SkScalar left, SkScalar top, SkScalar right, SkScalar bottom)
+{
+    fBox.set(left, top, right, bottom);
+}
+
+void SkTextBox::getSpacing(SkScalar* mul, SkScalar* add) const
+{
+    if (mul)
+        *mul = fSpacingMul;
+    if (add)
+        *add = fSpacingAdd;
+}
+
+void SkTextBox::setSpacing(SkScalar mul, SkScalar add)
+{
+    fSpacingMul = mul;
+    fSpacingAdd = add;
+}
+
+/////////////////////////////////////////////////////////////////////////////////////////////
+
+void SkTextBox::draw(SkCanvas* canvas, const char text[], size_t len, const SkPaint& paint)
+{
+    SkASSERT(canvas && &paint && (text || len == 0));
+
+    SkScalar marginWidth = fBox.width();
+
+    if (marginWidth <= 0 || len == 0)
+        return;
+
+    const char* textStop = text + len;
+
+    SkScalar                x, y, scaledSpacing, height, fontHeight;
+    SkPaint::FontMetrics    metrics;
+
+    switch (paint.getTextAlign()) {
+    case SkPaint::kLeft_Align:
+        x = 0;
+        break;
+    case SkPaint::kCenter_Align:
+        x = SkScalarHalf(marginWidth);
+        break;
+    default:
+        x = marginWidth;
+        break;
+    }
+    x += fBox.fLeft;
+
+    fontHeight = paint.getFontMetrics(&metrics);
+    scaledSpacing = SkScalarMul(fontHeight, fSpacingMul) + fSpacingAdd;
+    height = fBox.height();
+
+    //  compute Y position for first line
+    {
+        SkScalar textHeight = fontHeight;
+
+        if (fMode == kLineBreak_Mode && fSpacingAlign != kStart_SpacingAlign)
+        {
+            int count = SkTextLineBreaker::CountLines(text, textStop - text, paint, marginWidth);
+            SkASSERT(count > 0);
+            textHeight += scaledSpacing * (count - 1);
+        }
+
+        switch (fSpacingAlign) {
+        case kStart_SpacingAlign:
+            y = 0;
+            break;
+        case kCenter_SpacingAlign:
+            y = SkScalarHalf(height - textHeight);
+            break;
+        default:
+            SkASSERT(fSpacingAlign == kEnd_SpacingAlign);
+            y = height - textHeight;
+            break;
+        }
+        y += fBox.fTop - metrics.fAscent;
+    }
+
+    for (;;)
+    {
+        len = linebreak(text, textStop, paint, marginWidth);
+        if (y + metrics.fDescent + metrics.fLeading > 0)
+            canvas->drawText(text, len, x, y, paint);
+        text += len;
+        if (text >= textStop)
+            break;
+        y += scaledSpacing;
+        if (y + metrics.fAscent >= height)
+            break;
+    } 
+}
+