Hi Michael,Please note I'm using the plain (non-cairo) GTK backend. Going on what I found in the code it should have the same display effect as the riscos backend.
The lines between the cells were originally yellow, but when copying screens to my windows box they changed to red. I haven't investigated it yet, but my guess is that they are initialized colour values that use alpha channel. The lines should not be visible as they are 'holes' created by rounding errors. The fixed-point values I use have a 13 bit fraction which gives about 0.000122 accuracy. That leaves 18 bits for the integer part giving a range from -266142 to 266141. I am assuming the coordinate range is -65536 to 65535 which leaves some safety margin for overflow errors during intermediate calculations. I do not know what the specs say about coordinate and sizing ranges. In the plotter functions I added code which snap the coordinates to the display pixel grid. I have found in the rendering code extra calculations for scaling, but it originates as being zoom. I feel that zooming should be done by the plotters, not by the layout/renderer. Besides, delaying scaling increases accuracy.
Attached the HTML. Sorry about forgetting them in the first place.I also have to note that although the effects look promising (more accurate and no FP operations) there is a drawback. It is fixed point arithmetic and because of that you can apply any integer operation onto it. Extra discipline is required that fixed point calculations only involve proper scaled integer values. Sadly, C and GCC do not have the ability to validate this requirement. Luckily, validity can be achieved by using the operator overloading capability of C++. This implies that at a given moment, the source has to be pulled through C++ to verify proper fixed-point arithmetic usage.
Franz.
This looks interesting. What are the red lines in the integer/floating point one from? A table cell background? Are the lines meant to be visible or not? Can you send me the original HTML and image files? The fixed point one obviously looks better in the animations, although, the small red squares get bigger and smaller as it zooms in. Michael
<<inline: 2x2.gif>>
