move SkTextBox into utils

BUG=skia:
TBR=

Review URL: https://codereview.chromium.org/696293005

1 files changed, 259 insertions, 0 deletions

diff --git a/src/utils/SkTextBox.cpp b/src/utils/SkTextBox.cpp
new file mode 100644
index 0000000000..55d75a64da
--- /dev/null
+++ b/src/utils/SkTextBox.cpp
@@ -0,0 +1,259 @@
+/*
+ * Copyright 2006 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkTextBox.h"
+#include "SkUtils.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,
+                        size_t* trailing = NULL)
+{
+    size_t lengthBreak = paint.breakText(text, stop - text, margin);
+
+    //Check for white space or line breakers before the lengthBreak
+    const char* start = text;
+    const char* word_start = text;
+    int prevWS = true;
+    if (trailing) {
+        *trailing = 0;
+    }
+
+    while (text < stop) {
+        const char* prevText = text;
+        SkUnichar uni = SkUTF8_NextUnichar(&text);
+        int currWS = is_ws(uni);
+
+        if (!currWS && prevWS) {
+            word_start = prevText;
+        }
+        prevWS = currWS;
+
+        if (text > start + lengthBreak) {
+            if (currWS) {
+                // eat the rest of the whitespace
+                while (text < stop && is_ws(SkUTF8_ToUnichar(text))) {
+                    text += SkUTF8_CountUTF8Bytes(text);
+                }
+                if (trailing) {
+                    *trailing = text - prevText;
+                }
+            } else {
+                // backup until a whitespace (or 1 char)
+                if (word_start == start) {
+                    if (prevText > start) {
+                        text = prevText;
+                    }
+                } else {
+                    text = word_start;
+                }
+            }
+            break;
+        }
+
+        if ('\n' == uni) {
+            size_t ret = text - start;
+            size_t lineBreakSize = 1;
+            if (text < stop) {
+                uni = SkUTF8_NextUnichar(&text);
+                if ('\r' == uni) {
+                    ret = text - start;
+                    ++lineBreakSize;
+                }
+            }
+            if (trailing) {
+                *trailing = lineBreakSize;
+            }
+            return ret;
+        }
+
+        if ('\r' == uni) {
+            size_t ret = text - start;
+            size_t lineBreakSize = 1;
+            if (text < stop) {
+                uni = SkUTF8_NextUnichar(&text);
+                if ('\n' == uni) {
+                    ret = text - start;
+                    ++lineBreakSize;
+                }
+            }
+            if (trailing) {
+                *trailing = lineBreakSize;
+            }
+            return ret;
+        }
+    }
+
+    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 && (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 (;;)
+    {
+        size_t trailing;
+        len = linebreak(text, textStop, paint, marginWidth, &trailing);
+        if (y + metrics.fDescent + metrics.fLeading > 0)
+            canvas->drawText(text, len - trailing, x, y, paint);
+        text += len;
+        if (text >= textStop)
+            break;
+        y += scaledSpacing;
+        if (y + metrics.fAscent >= fBox.fBottom)
+            break;
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+void SkTextBox::setText(const char text[], size_t len, const SkPaint& paint) {
+    fText = text;
+    fLen = len;
+    fPaint = &paint;
+}
+
+void SkTextBox::draw(SkCanvas* canvas) {
+    this->draw(canvas, fText, fLen, *fPaint);
+}
+
+int SkTextBox::countLines() const {
+    return SkTextLineBreaker::CountLines(fText, fLen, *fPaint, fBox.width());
+}
+
+SkScalar SkTextBox::getTextHeight() const {
+    SkScalar spacing = SkScalarMul(fPaint->getTextSize(), fSpacingMul) + fSpacingAdd;
+    return this->countLines() * spacing;
+}