The code in this book was developed for and tested on particular library versions, including Python 3.14, Skia 138, Tk 8.6.14, DukPy 0.3.0, and PySDL2 0.9.15. Earlier editions of the book, however, relied on earlier versions, and future editions might rely on later ones. This page documents code changes necessary to port the code of Web Browser Engineering to other relevant releases of each library. It will be regularly updated as new versions are released and tested.

Porting to Skia 87

The text of this online book uses Skia 138, but the printed 1^st printed edition used the earlier version 87. This earlier version was missing the SamplingOptions API used in Chapter 15 of this book. Skia 87 instead provides the older FilterQuality API.

Readers of the 1^st printed edition thus saw a different implementation of parse_image_rendering:

def parse_image_rendering(quality):
    if quality == "high-quality":
        return skia.FilterQuality.kHigh_FilterQuality
    elif quality == "crisp-edges":
        return skia.FilterQuality.kLow_FilterQuality
    else:
        return skia.FilterQuality.kMedium_FilterQuality

And changing the execute method of DrawImage like so:

class DrawImage:
    def execute(self, canvas):
        paint = skia.Paint(
            FilterQuality=self.quality,
        )
        canvas.drawImageRect(self.image, self.rect, paint)

The SDL_GL_SetAttribute method calls in the Browser constructor were also not necessary on this older version.

We recommend new readers use a recent Skia version, as described in the main text, but the old code is provided here for owners of the 1^st printed edition.