public bool PrepareLetterDefinitions(string text)
{
List <char> newChars = new List <char>();
FindNewCharacters(text, ref newChars);
if (newChars.Count == 0)
{
return(false);
}
var newCharString = new string(newChars.ToArray());
var glyphs = _TextPaint.GetGlyphs(newCharString);
var glyphWidths = _TextPaint.GetGlyphWidths(newCharString);
for (int i = 0; i < glyphs.Length; i++)
{
FontLetterDefinition tempDef = new FontLetterDefinition();
if (glyphs[i] == 0)
{
_LetterDefinitions[newCharString[i]] = tempDef;
}
else
{
tempDef.ValidDefinition = true;
tempDef.AdvanceX = glyphWidths[i];
_LetterDefinitions[newCharString[i]] = tempDef;
}
}
return(true);
}
/// <summary>
/// Calculate any overhang for this text line
/// </summary>
/// <param name="right"></param>
/// <param name="leftOverhang"></param>
/// <param name="rightOverhang"></param>
internal void UpdateOverhang(float right, ref float leftOverhang, ref float rightOverhang)
{
if (RunKind == FontRunKind.TrailingWhitespace)
{
return;
}
if (Glyphs.Length == 0)
{
return;
}
using (var paint = new SKPaint())
{
float glyphScale = 1;
if (Style.FontVariant == FontVariant.SuperScript)
{
glyphScale = 0.65f;
}
if (Style.FontVariant == FontVariant.SubScript)
{
glyphScale = 0.65f;
}
paint.TextEncoding = SKTextEncoding.GlyphId;
paint.Typeface = Typeface;
paint.TextSize = Style.FontSize * glyphScale;
paint.SubpixelText = true;
paint.IsAntialias = true;
paint.LcdRenderText = false;
unsafe
{
fixed(ushort *pGlyphs = Glyphs.Underlying)
{
paint.GetGlyphWidths((IntPtr)(pGlyphs + Start), sizeof(ushort) * Glyphs.Length, out var bounds);
if (bounds != null)
{
for (int i = 0; i < bounds.Length; i++)
{
float gx = GlyphPositions[i].X;
var loh = -(gx + bounds[i].Left);
if (loh > leftOverhang)
{
leftOverhang = loh;
}
var roh = (gx + bounds[i].Right + 1) - right;
if (roh > rightOverhang)
{
rightOverhang = roh;
}
}
}
}
}
}
}
public void GetGlyphWidthsReturnsTheCorrectAmount()
{
var paint = new SKPaint();
var widths = paint.GetGlyphWidths("Hello World!", out var bounds);
Assert.Equal(widths.Length, bounds.Length);
}
private static void DrawSkia(SKCanvas canvas, SKImageInfo info, SKBitmap skBitmap, string text)
{
// get the screen density for scaling
var scale = 1f;
var scaledSize = new SKSize(info.Width / scale, info.Height / scale);
// handle the device screen density
canvas.Scale(scale);
// make sure the canvas is blank
canvas.Clear(SKColors.Pink);
var scaleBg = skBitmap.Width * 1f / skBitmap.Height;
var scalePanel = 16 * 1f / 9;
var left = 0f;
var top = 0f;
var size = new SKSize(0, 0);
if (scaleBg > scalePanel)
{
size.Height = scaledSize.Height;
size.Width = size.Height * scaleBg;
left = (scaledSize.Width - size.Width) / 2;
}
else
{
//size.Width = scaledSize.Width;
//size.Height = size.Width / scaleBg;
//top = (scaledSize.Height - size.Height) / 2;
size.Height = scaledSize.Height;
size.Width = size.Height * scaleBg;
left = (scaledSize.Width - size.Width) / 2;
}
canvas.DrawBitmap(skBitmap, new SKRect(left, top,
left + size.Width, top + size.Height));
// draw some text
var paint = new SKPaint
{
Color = SKColors.Black,
IsAntialias = true,
Style = SKPaintStyle.Fill,
TextAlign = SKTextAlign.Center,
TextSize = 50
};
var widths = paint.GetGlyphWidths(text);
var total = widths.Sum() / 2;
//var coord = new SKPoint(scaledSize.Width / 2, (scaledSize.Height + paint.TextSize) / 2);
var coord = new SKPoint(left + 20 + total, 20 + paint.TextSize);
canvas.DrawText(text, coord, paint);
}
public void GetGlyphWidthsAreCorrect()
{
var paint = new SKPaint();
var widths = paint.GetGlyphWidths("Hello World!", out var bounds);
// make sure the 'l' glyphs are the same width
Assert.True(widths[2] > 0);
Assert.True(widths[2] == widths[3]);
Assert.True(widths[2] == widths[9]);
// make sure the 'l' bounds are the same size
Assert.False(bounds[2].IsEmpty);
Assert.True(bounds[2] == bounds[3]);
Assert.True(bounds[2] == bounds[9]);
// make sure the 'l' and 'W' glyphs are NOT the same width
Assert.True(widths[2] != widths[6]);
// make sure the 'l' and 'W' bounds are NOT the same width
Assert.True(bounds[2] != bounds[6]);
}
/// <summary>
/// Constructs a new TextShaper
/// </summary>
/// <param name="typeface">The typeface of this shaper</param>
private TextShaper(SKTypeface typeface)
{
// Store typeface
_typeface = typeface;
// Load the typeface stream to a HarfBuzz font
int index;
using (var blob = GetHarfBuzzBlob(typeface.OpenStream(out index)))
using (var face = new Face(blob, (uint)index))
{
face.UnitsPerEm = typeface.UnitsPerEm;
_font = new HarfBuzzSharp.Font(face);
_font.SetScale(overScale, overScale);
_font.SetFunctionsOpenType();
}
// Get font metrics for this typeface
using (var paint = new SKPaint())
{
paint.Typeface = typeface;
paint.TextSize = overScale;
_fontMetrics = paint.FontMetrics;
// This is a temporary hack until SkiaSharp exposes
// a way to check if a font is fixed pitch. For now
// we just measure and `i` and a `w` and see if they're
// the same width.
float[] widths = paint.GetGlyphWidths("iw", out var rects);
_isFixedPitch = widths != null && widths.Length > 1 && widths[0] == widths[1];
if (_isFixedPitch)
{
_fixedCharacterWidth = widths[0];
}
}
}
internal unsafe void Run()
{
if (!needRun)
{
return;
}
lines.Clear();
//设置paint参数
var paint = new SKPaint();
paint.TextEncoding = SKTextEncoding.Utf16;
font.ApplyToSKPaint(paint, GraphicsUnit.Pixel, dpi); //注意目标类型为像素
//测量FontMetric
SKFontMetrics metrics = font.FontMetrics;
//根据文字排版方向确认限宽及限高
float maxWidth = Math.Min(32767, IsVertical ? height : width); //TODO:
float maxHeight = IsVertical ? width : height;
//TODO:计算高度不满足一行的情况
fixed(char *ptr = Text)
{
byte *textPtr = (byte *)ptr;
byte *startTextPtr = (byte *)ptr;
int totalBytes = text.Length * 2;
int leftBytes = totalBytes;
float y = 0;
while (true)
{
//根据是否允许换行，调用不同的breakText方法
var measuredWidth = 0f;
var lineBytes = (int)paint.BreakText(new IntPtr(startTextPtr), new IntPtr(leftBytes), maxWidth, out measuredWidth);
//var lineBytes = SkiaApi.sk_paint_break_text_icu(paint, new IntPtr(startTextPtr), leftBytes, maxWidth, null); //TODO:***** fix maxWidth
var newLine = new TextLayoutLine(this);
newLine.startByteIndex = (int)(startTextPtr - textPtr);
newLine.byteLength = lineBytes;
newLine.widths = paint.GetGlyphWidths(new IntPtr(startTextPtr), lineBytes);
//newLine.startCharIndex = 0; //TODO:
//根据对齐方式计算Line的offsetX值
if (stringFormat != null && stringFormat.Alignment != StringAlignment.Near)
{
//计算当前行Ink总宽度
float lineInkWidth = 0f;
for (int i = 0; i < newLine.widths.Length; i++)
{
lineInkWidth += newLine.widths[i];
}
float lineSpace = width - lineInkWidth;
if (lineSpace > 0f)
{
if (stringFormat.Alignment == StringAlignment.Center)
{
newLine.offsetX = lineSpace / 2f;
}
else if (stringFormat.Alignment == StringAlignment.Far)
{
newLine.offsetX = lineSpace;
}
}
}
//添加新行
lines.Add(newLine);
//判断是否允许换行，不允许直接退出循环
if (IsNoWrap)
{
break;
}
//计算下一行高度是否超出限高
y = y - metrics.Ascent + metrics.Descent + metrics.Leading;
if ((y - metrics.Ascent + metrics.Descent) > maxHeight)
{
break;
}
//偏移剩余部分，并判断是否全部计算完毕
startTextPtr += lineBytes;
if ((int)(startTextPtr - textPtr) >= totalBytes)
{
break;
}
leftBytes -= lineBytes;
}
}
//根据对齐方式计算offsetY的值
CalcOffsetY();
needRun = false;
}
