使用php中的imagefilter（）使图像清晰

Question

Is there any possibilities to make image more sharp using imagefilter() function? I am using imagettftext() which adds Anti-aliasing to fonts and the fonts looks bit de-focused. I like to make my final image bit sharpen so that I can reduce the blur around the char's in my image.

Different Test Images

• Font used
  • Roboto-Thin.ttf
  • Roboto-Black.ttf

Image with light fonts

I like to have my fonts to look something like those lines next to it.

Image with dark fonts

Image with -$font_color (Some web resources suggested to make font colour value to negative which basically turns off the anti-aliasing) But in this case the fonts looks ugly. (Left-To-Right 100 is with turned off anti-aliasing)

Answer 1

GD Solution

$old = "old.png";
$new = "new.png";

$im = imagecreatefrompng($imgname);
imagetruecolortopalette($im, FALSE, 256);
imagecolorset($im, imagecolorclosest($im, 159, 159, 159), 0, 0, 0);
imagecolorset($im, imagecolorclosest($im, 191, 191, 191), 0, 0, 0);

imagepng($im, $new);
imagedestroy($im);

Image Magic Solution

convert old.png -fuzz 0% -fill rgb(0,0,0) -opaque rgb(159,159,159) new.png
convert new.png -fuzz 0% -fill rgb(0,0,0) -opaque rgb(191,191,191) new.png

They would output

                  Old                           new