private static int Kerning(QFontGlyph g1, QFontGlyph g2, XLimits[] lim1, XLimits[] lim2, QFontKerningConfiguration config) { int yOffset1 = g1.yOffset; int yOffset2 = g2.yOffset; int startY = Math.Max(yOffset1, yOffset2); int endY = Math.Min(g1.rect.Height + yOffset1, g2.rect.Height + yOffset2); int w1 = g1.rect.Width; int worstCase = w1; //TODO - offset startY, endY by yOffset1 so that lim1[j-yOffset1] can be written as lim1[j], will need another var for yOffset2 for (int j = startY; j < endY; j++) worstCase = Math.Min(worstCase, w1 - lim1[j-yOffset1].Max + lim2[j-yOffset2].Min); worstCase = Math.Min(worstCase, g1.rect.Width); worstCase = Math.Min(worstCase, g2.rect.Width); //modify by character kerning rules CharacterKerningRule kerningRule = config.GetOverridingCharacterKerningRuleForPair(""+g1.character + g2.character); if (kerningRule == CharacterKerningRule.Zero) { return 0; } else if (kerningRule == CharacterKerningRule.NotMoreThanHalf) { return (int)Math.Min(Math.Min(g1.rect.Width,g2.rect.Width)*0.5f, worstCase); } return worstCase; }
public static Dictionary<String, int> CalculateKerning(char[] charSet, QFontGlyph[] glyphs, List<QBitmap> bitmapPages, QFontKerningConfiguration config) { var kerningPairs = new Dictionary<String, int>(); //we start by computing the index of the first and last non-empty pixel in each row of each glyph XLimits[][] limits = new XLimits[charSet.Length][]; int maxHeight = 0; for (int n = 0; n < charSet.Length; n++) { var rect = glyphs[n].rect; var page = bitmapPages[glyphs[n].page]; limits[n] = new XLimits[rect.Height]; maxHeight = Math.Max(rect.Height, maxHeight); int yStart = rect.Y; int yEnd = rect.Y + rect.Height; int xStart = rect.X; int xEnd = rect.X + rect.Width; for (int j = yStart; j < yEnd; j++) { int last = xStart; bool yetToFindFirst = true; for (int i = xStart; i < xEnd; i++) { if (!QBitmap.EmptyAlphaPixel(page.bitmapData, i, j,config.alphaEmptyPixelTolerance)) { if (yetToFindFirst) { limits[n][j - yStart].Min = i - xStart; yetToFindFirst = false; } last = i; } } limits[n][j - yStart].Max = last - xStart; if (yetToFindFirst) limits[n][j - yStart].Min = xEnd - 1; } } //we now bring up each row to the max (or min) of it's two adjacent rows, this is to stop glyphs sliding together too closely var tmp = new XLimits[maxHeight]; for (int n = 0; n < charSet.Length; n++) { //clear tmp for (int j = 0; j < limits[n].Length; j++) tmp[j] = limits[n][j]; for (int j = 0; j < limits[n].Length; j++) { if(j != 0){ tmp[j].Min = Math.Min(limits[n][j - 1].Min, tmp[j].Min); tmp[j].Max = Math.Max(limits[n][j - 1].Max, tmp[j].Max); } if (j != limits[n].Length - 1) { tmp[j].Min = Math.Min(limits[n][j + 1].Min, tmp[j].Min); tmp[j].Max = Math.Max(limits[n][j + 1].Max, tmp[j].Max); } } for (int j = 0; j < limits[n].Length; j++) limits[n][j] = tmp[j]; } for (int i = 0; i < charSet.Length; i++) for (int j = 0; j < charSet.Length; j++) kerningPairs.Add("" + charSet[i] + charSet[j], 1-Kerning(glyphs[i], glyphs[j], limits[i], limits[j],config)); return kerningPairs; }