gdImagePtr rs_gdImageThickLineBrush(int line_weight, RS_Color& color)
{
if (line_weight % 2 == 1)
line_weight += 1;
int sx = line_weight;
int sy = line_weight;
gdImagePtr brush = gdImageCreateTrueColor(sx, sy);
int transparent = gdImageColorAllocateAlpha(brush, 0, 0, 0, 127);
gdImageAlphaBlending(brush, 0);
gdImageFilledRectangle(brush, 0, 0, sx, sy, transparent);
//compute fractional alpha value for antialiasing effect
//each pixel should be hit by line_weight / 2 number of circles
//so the alpha is computed as 255 / line_weight * 2
RS_Color falpha = color;
falpha.alpha() = falpha.alpha() / line_weight * 2 + 1;
falpha.alpha() = (falpha.alpha() < 255)? falpha.alpha() : 255;
//outer transparent circle -- for antialiased effect
rs_gdImageCircleForBrush(brush, sx/2, sy/2, line_weight / 2, falpha);
gdImageAlphaBlending(brush, 1);
//inner non-transparent circle
rs_gdImageCircleForBrush(brush, sx/2, sy/2, (line_weight - 2) / 2, color);
return brush;
}
//axis aligned circle for setting up brushes for thick lines
void rs_gdImageCircleForBrush(gdImagePtr im, int x, int y, int rad, RS_Color& color)
{
int gdc = ConvertColor(im, color);
float rad2 = (float)rad*rad;
for (int j = -rad, k = y+j; j <= rad; j++, k++)
{
float j_offset = j + 0.5f;
float hlen = sqrt(rad2 - j_offset*j_offset);
int solidwid = (int)hlen;
if (solidwid)
gdImageLine(im, x-solidwid, k, x+solidwid-1, k, gdc);
float aalpha = hlen - solidwid;
RS_Color ac = color;
ac.alpha() = (int)(ac.alpha() * aalpha);
int gdc2 = ConvertColor(im, ac);
gdImageSetPixel(im, x-solidwid-1, k, gdc2);
gdImageSetPixel(im, x+solidwid, k, gdc2);
}
}
int ConvertColor(gdImagePtr i, RS_Color& c)
{
return gdImageColorAllocateAlpha(i, c.red(), c.green(), c.blue(), 127 - c.alpha()/2 );
}
bool GeometryAdapter::EvalColor(const MdfModel::MdfString& exprstr, RS_Color& rscolor)
{
// TODO: needs an expression processor argument to eval expressions
// string is in the form "AARRGGBB"
const wchar_t* scolor = exprstr.c_str();
size_t len = wcslen(scolor);
unsigned int color = 0;
bool isConst = false;
// try to check if the expression is constant
int status = 0;
if (len == 0)
{
// error or a color was not set
// use transparent black which indicates "not set"
rscolor = RS_Color(RS_Color::EMPTY_COLOR_RGBA);
return true;
}
else if (len == 8)
{
status = swscanf(scolor, L"%8X", &color);
}
else if (len == 6)
{
status = swscanf(scolor, L"%6X", &color);
// there was no alpha specified in the constant string, add it
color |= 0xFF000000;
}
if (status != 1)
{
// if not constant try to evaluate as expression
if (!m_exec)
{
_ASSERT(false);
rscolor = RS_Color(0x000000FF);
return true;
}
FdoExpression* expr = ObtainFdoExpression(&exprstr);
// make sure we have a parsed expression
if (!expr)
{
_ASSERT(false);
rscolor = RS_Color(0x000000FF);
return false;
}
try
{
FdoPtr<FdoLiteralValue> lval = m_exec->Evaluate(expr);
color = (unsigned int)ExpressionHelper::GetAsInt32(lval.p);
}
catch (FdoException* e)
{
ProcessStylizerException(e, __LINE__, __WFILE__);
rscolor = RS_Color(0x000000FF);
return false;
}
catch (...)
{
return false;
}
}
else
{
isConst = true;
}
rscolor.alpha() = color >> 24;
rscolor.red() = (color >> 16) & 0xFF;
rscolor.green() = (color >> 8) & 0xFF;
rscolor.blue() = color & 0xFF;
return isConst;
}