tsai
/
Avalonia
mirror of https://github.com/AvaloniaUI/Avalonia.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
Browse Source

skia new line and line break rendering improvements

pull/559/head
donandren 10 years ago
parent
6161bcb886
commit
c84b5d863d
1 changed files with 256 additions and 121 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 377
      src/Skia/Avalonia.Skia/FormattedTextImpl.cs

377
src/Skia/Avalonia.Skia/FormattedTextImpl.cs
View File

@ -5,32 +5,28 @@ using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Text;
using System.Linq;
namespace Avalonia.Skia
{
unsafe class FormattedTextImpl : IFormattedTextImpl
{
public SKPaint Paint { get; private set; }
public FormattedTextImpl(string text, TextWrapping wrapping = TextWrapping.NoWrap)
{
_text = text;
_wrapping = wrapping;
Paint = new SKPaint();
_paint = new SKPaint();
//currently Skia does not measure properly with Utf8 !!!
//Paint.TextEncoding = SKTextEncoding.Utf8;
Paint.TextEncoding = SKTextEncoding.Utf16;
Paint.IsStroke = false;
Paint.IsAntialias = true;
_paint.TextEncoding = SKTextEncoding.Utf16;
_paint.IsStroke = false;
_paint.IsAntialias = true;
LineOffset = 0;
// Replace 0 characters with zero-width spaces (200B)
_text = _text.Replace((char)0, (char)0x200B);
//Replace \r\n with \r zero width space and \n with \r
//as in Skia looks like only \r is rendered properly
_text = _text.Replace("\r\n", "\r\u200B").Replace('\n', '\r');
}
public static FormattedTextImpl Create(string text, string fontFamilyName, double fontSize, FontStyle fontStyle,
@ -39,33 +35,33 @@ namespace Avalonia.Skia
var typeface = TypefaceCache.GetTypeface(fontFamilyName, fontStyle, fontWeight);
FormattedTextImpl instance = new FormattedTextImpl(text, wrapping);
instance.Paint.Typeface = typeface;
instance.Paint.TextSize = (float)fontSize;
instance.Paint.TextAlign = textAlignment.ToSKTextAlign();
instance._paint.Typeface = typeface;
instance._paint.TextSize = (float)fontSize;
instance._paint.TextAlign = textAlignment.ToSKTextAlign();
instance.Rebuild();
return instance;
}
private readonly SKPaint _paint;
private readonly string _text;
private readonly TextWrapping _wrapping;
readonly List<FormattedTextLine> _lines = new List<FormattedTextLine>();
readonly List<Rect> _rects = new List<Rect>();
List<AvaloniaFormattedTextLine> _skiaLines;
SKRect[] _skiaRects;
private readonly List<FormattedTextLine> _lines = new List<FormattedTextLine>();
private readonly List<Rect> _rects = new List<Rect>();
Size _size;
private List<AvaloniaFormattedTextLine> _skiaLines;
private Size _size;
const float MAX_LINE_WIDTH = 10000;
float LineOffset;
float WidthConstraint = -1;
TextWrapping _wrapping;
private float LineOffset;
private float LineHeight;
struct AvaloniaFormattedTextLine
{
public float Top;
public int Start;
public int Length;
public int TextLength;
public float Height;
public float Width;
};
@ -77,17 +73,44 @@ namespace Avalonia.Skia
public TextHitTestResult HitTestPoint(Point point)
{
for (int c = 0; c < _rects.Count; c++)
float y = (float)point.Y;
var line = _skiaLines.Find(l => l.Top <= y && (l.Top + l.Height) > y);
var rects = GetRects();
if (!line.Equals(default(AvaloniaFormattedTextLine)))
{
//TODO: Detect line first
var rc = _rects[c];
if (rc.Contains(point))
for (int c = line.Start; c < line.Start + line.TextLength; c++)
{
//TODO: Detect line first
var rc = rects[c];
if (rc.Contains(point))
{
return new TextHitTestResult
{
IsInside = true,
TextPosition = c,
IsTrailing = (point.X - rc.X) > rc.Width / 2
};
}
}
if (point.X >= line.Width)
{
return new TextHitTestResult
{
IsInside = false,
TextPosition = line.Start + line.Length > 0 ? line.Length - 1 : 0,
IsTrailing = true
};
}
else
{
return new TextHitTestResult
{
IsInside = true,
TextPosition = c,
IsTrailing = (point.X - rc.X) > rc.Width / 2
IsInside = line.Length > 0,
TextPosition = line.Start,
IsTrailing = false
};
}
}
@ -97,15 +120,32 @@ namespace Avalonia.Skia
public Rect HitTestTextPosition(int index)
{
if (index < 0 || index >= _rects.Count)
var rects = GetRects();
if (index < 0 || index > rects.Count)
return new Rect();
return _rects[index];
if (rects.Count == 0)
{
//empty text
return new Rect(0, 0, 1, LineHeight);
}
if (index == rects.Count)
{
var lr = rects[rects.Count - 1];
return new Rect(new Point(lr.X + lr.Width, lr.Y), rects[index - 1].Size);
}
return rects[index];
}
public IEnumerable<Rect> HitTestTextRange(int index, int length)
{
var rects = GetRects();
for (var c = 0; c < length; c++)
yield return _rects[c + index];
yield return rects[c + index];
}
public Size Measure()
@ -123,128 +163,75 @@ namespace Avalonia.Skia
var length = _text.Length;
_lines.Clear();
_skiaRects = new SKRect[length];
_rects.Clear();
_skiaLines = new List<AvaloniaFormattedTextLine>();
int curOff = 0;
float curY = 0;
var metrics = Paint.FontMetrics;
var metrics = _paint.FontMetrics;
var mTop = metrics.Top; // The greatest distance above the baseline for any glyph (will be <= 0).
var mBottom = metrics.Bottom; // The greatest distance below the baseline for any glyph (will be >= 0).
var mLeading = metrics.Leading; // The recommended distance to add between lines of text (will be >= 0).
var mDescent = metrics.Descent;
// This seems like the best measure of full vertical extent
float lineHeight = mBottom - mTop;
LineHeight = mBottom - mTop;
// Rendering is relative to baseline
LineOffset = -metrics.Top;
string subString;
float widthConstraint = (_constraint.Width != double.PositiveInfinity)
? (float)_constraint.Width
: -1;
for (int c = 0; curOff < length; c++)
{
float lineWidth = -1;
int measured;
int extraSkip = 0;
int trailingnumber = 0;
subString = _text.Substring(curOff);
if (_wrapping == TextWrapping.NoWrap)
{
measured = length - curOff;
}
else
float constraint = -1;
if (_wrapping == TextWrapping.Wrap)
{
float constraint = WidthConstraint <= 0 ? MAX_LINE_WIDTH : WidthConstraint;
constraint = widthConstraint <= 0 ? MAX_LINE_WIDTH : widthConstraint;
if (constraint > MAX_LINE_WIDTH)
constraint = MAX_LINE_WIDTH;
measured = (int)Paint.BreakText(subString, constraint, out lineWidth) / 2;
}
int newLineIndex = subString.IndexOf('\r');
measured = LineBreak(_text, curOff, length, _paint, constraint, out trailingnumber);
if (newLineIndex > -1 && measured >= newLineIndex)
{
measured = newLineIndex > 0 ? newLineIndex + 1 : 0;
}
if (measured == 0)
{
measured = 1;
lineWidth = -1;
}
AvaloniaFormattedTextLine line = new AvaloniaFormattedTextLine();
line.TextLength = measured;
if (_wrapping == TextWrapping.Wrap)
{
char nextChar = ' ';
if (curOff + measured < length)
nextChar = _text[curOff + measured];
subString = _text.Substring(line.Start, line.TextLength);
lineWidth = _paint.MeasureText(subString);
var b2 = char.IsWhiteSpace(' ');
var b1 = char.IsWhiteSpace('\u200B');
if (nextChar != ' ' && nextChar != '\u200B' && nextChar != '\r')
{
// Perform scan for the last space or zero width space and end the line there
for (int si = curOff + measured - 1; si > curOff; si--)
{
if (_text[si] == ' ' || _text[si] == '\u200B')
{
measured = si - curOff;
extraSkip = 1;
break;
}
}
}
}
AvaloniaFormattedTextLine line = new AvaloniaFormattedTextLine();
// lineHeight = hh;
line.Start = curOff;
line.Length = measured;
line.Length = measured - trailingnumber;
line.Width = lineWidth;
line.Height = lineHeight;
line.Height = LineHeight;
line.Top = curY;
if (line.Width < 0)
line.Width = _skiaRects[line.Start + line.Length - 1].Right;
// Build character rects
for (int i = line.Start; i < line.Start + line.Length; i++)
{
float prevRight = 0;
if (i != line.Start)
prevRight = _skiaRects[i - 1].Right;
subString = _text.Substring(line.Start, i - line.Start + 1);
float w = Paint.MeasureText(subString);
SKRect rc;
rc.Left = prevRight;
rc.Right = w;
rc.Top = line.Top;
rc.Bottom = line.Top + line.Height;
_skiaRects[i] = rc;
}
subString = _text.Substring(line.Start, line.Length);
line.Width = Paint.MeasureText(subString);
_skiaLines.Add(line);
curY += lineHeight;
curY += LineHeight - mDescent;
// TODO: We may want to consider adding Leading to the vertical line spacing but for now
// it appears to make no difference. Revisit as part of FormattedText improvements.
//
//curY += mLeading;
curOff += measured + extraSkip;
curOff += measured;
}
// Now convert to Avalonia data formats
_lines.Clear();
_rects.Clear();
float maxX = 0;
for (var c = 0; c < _skiaLines.Count; c++)
@ -256,11 +243,6 @@ namespace Avalonia.Skia
_lines.Add(new FormattedTextLine(_skiaLines[c].Length, _skiaLines[c].Height));
}
for (var c = 0; c < _text.Length; c++)
{
_rects.Add(_skiaRects[c].ToAvaloniaRect());
}
if (_skiaLines.Count == 0)
{
_size = new Size();
@ -270,11 +252,52 @@ namespace Avalonia.Skia
var lastLine = _skiaLines[_skiaLines.Count - 1];
_size = new Size(maxX, lastLine.Top + lastLine.Height);
}
BuildRects();
}
private List<Rect> GetRects()
{
if (_text.Length > _rects.Count)
{
BuildRects();
}
return _rects;
}
private void BuildRects()
{
// Build character rects
var fm = _paint.FontMetrics;
for (int li = 0; li < _skiaLines.Count; li++)
{
var line = _skiaLines[li];
float prevRight = 0;
double nextTop = line.Top + line.Height;
if (li + 1 < _skiaLines.Count)
{
nextTop = _skiaLines[li + 1].Top;
}
for (int i = line.Start; i < line.Start + line.TextLength; i++)
{
float w = _paint.MeasureText(_text[i].ToString());
_rects.Add(new Rect(
prevRight,
line.Top,
w,
nextTop - line.Top));
prevRight += w;
}
}
}
internal void Draw(SKCanvas canvas, SKPoint origin, DrawingContextImpl.PaintWrapper foreground)
{
SKPaint paint = Paint;
SKPaint paint = _paint;
/* TODO: This originated from Native code, it might be useful for debugging character positions as
* we improve the FormattedText support. Will need to port this to C# obviously. Rmove when
@ -316,8 +339,8 @@ namespace Avalonia.Skia
//TODO: find a better implementation including
//hittesting and text selection working properly
paint.TextAlign = SKTextAlign.Right;
if(paint.TextAlign == SKTextAlign.Left)
//paint.TextAlign = SKTextAlign.Right;
if (paint.TextAlign == SKTextAlign.Left)
{
x = origin.X;
}
@ -327,10 +350,10 @@ namespace Avalonia.Skia
Constraint.Width :
_size.Width;
switch (Paint.TextAlign)
switch (_paint.TextAlign)
{
case SKTextAlign.Center: x = origin.X + (float)width/2; break;
case SKTextAlign.Right: x = origin.X + (float) width; break;
case SKTextAlign.Center: x = origin.X + (float)width / 2; break;
case SKTextAlign.Right: x = origin.X + (float)width; break;
}
}
@ -351,9 +374,6 @@ namespace Avalonia.Skia
return;
_constraint = value;
WidthConstraint = (_constraint.Width != double.PositiveInfinity)
? (float)_constraint.Width
: -1;
Rebuild();
}
@ -367,5 +387,120 @@ namespace Avalonia.Skia
public void Dispose()
{
}
private static bool IsBreakChar(char c)
{
//white space or zero space whitespace
return char.IsWhiteSpace(c) || c == '\u200B';
}
private static int LineBreak(string textInput, int textIndex, int stop,
SKPaint paint, float maxWidth,
out int trailingCount)
{
int lengthBreak;
if (maxWidth == -1)
{
lengthBreak = stop - textIndex;
}
else
{
float measuredWidth;
string subText = textInput.Substring(textIndex, stop - textIndex);
lengthBreak = (int)paint.BreakText(subText, maxWidth, out measuredWidth) / 2;
}
//Check for white space or line breakers before the lengthBreak
int startIndex = textIndex;
int index = textIndex;
int word_start = textIndex;
bool prevBreak = true;
trailingCount = 0;
while (index < stop)
{
int prevText = index;
char currChar = textInput[index++];
bool currBreak = IsBreakChar(currChar);
if (!currBreak && prevBreak)
{
word_start = prevText;
}
prevBreak = currBreak;
if (index > startIndex + lengthBreak)
{
if (currBreak)
{
// eat the rest of the whitespace
while (index < stop && IsBreakChar(textInput[index]))
{
index++;
}
trailingCount = index - prevText;
}
else
{
// backup until a whitespace (or 1 char)
if (word_start == startIndex)
{
if (prevText > startIndex)
{
index = prevText;
}
}
else
{
index = word_start;
}
}
break;
}
if ('\n' == currChar)
{
int ret = index - startIndex;
int lineBreakSize = 1;
if (index < stop)
{
currChar = textInput[index++];
if ('\r' == currChar)
{
ret = index - startIndex;
++lineBreakSize;
}
}
trailingCount = lineBreakSize;
return ret;
}
if ('\r' == currChar)
{
int ret = index - startIndex;
int lineBreakSize = 1;
if (index < stop)
{
currChar = textInput[index++];
if ('\n' == currChar)
{
ret = index - startIndex;
++lineBreakSize;
}
}
trailingCount = lineBreakSize;
return ret;
}
}
return index - startIndex;
}
}
}
Write Preview
Loading…
Cancel
Save