\[ y'(x)=x \sqrt {x^2+4 y(x)-4 x}-\frac {x}{2}+1 \] ✓ Mathematica : cpu = 0.755841 (sec), leaf count = 94
DSolve[Derivative[1][y][x] == 1 - x/2 + x*Sqrt[-4*x + x^2 + 4*y[x]],y[x],x]
\[\text {Solve}\left [-\frac {1}{2} \sqrt {x^2+4 y(x)-4 x}+\log \left (-\sqrt {x^2+4 y(x)-4 x}-x+2\right )-\tanh ^{-1}\left (\frac {2 x-4}{2 \sqrt {x^2+4 y(x)-4 x}}\right )+\frac {x^2}{2}-\frac {1}{2} \log (2-2 y(x))=c_1,y(x)\right ]\] ✓ Maple : cpu = 0.304 (sec), leaf count = 24
dsolve(diff(y(x),x) = -1/2*x+1+x*(x^2-4*x+4*y(x))^(1/2),y(x))
\[c_{1}+x^{2}+\frac {1}{2}-\sqrt {x^{2}-4 x +4 y \left (x \right )} = 0\]