I'm seeking feedback on my changes to make the knockout plotting optional based on the plotter backend (patch attached). I've added a new entry 'option_knockout' to 'struct plotter_table' which basically is a request from that plotter backend for the content redraw routine to get called in such a way that overlapping render areas are avoided as much as possible (that's what I'm assuming the knockout.c code is doing). However, it is up to the content redraw code to actually implement this option if it is reasonably profitable. This was and is currently done explicitly by the html content redraw code. On top of that the riscos plotter code was installing the knockout plotter itself for all content types except plaintext and SVG and this is no longer being done in this patch. In patch more detail: - desktop/plotters.h: added struct plotter_table::option_knockout - render/html_redraw.c(html_redraw): if the plotter backend wants the knockout calling behaviour, install the knockout plotter which will then call the real backend. Also check on the return values of clg and clip plotter calls. - Plotter backend changes: -> no longer plotting in knockout mode: - gtk/gtk_print.c: BTW, also removed what I think is a 2nd instance of "struct plotter_table plot" (the first one is in gtk/gtk_plotters.c), right ? - riscos/save_draw.c - riscos/print.c: in addition I noticed that the path plotter function pointer wasn't filled in and this is now fixed. - pdf/pdf_plotters.c: I also removed the flush function as this is optional and we only had a dummy implementation there. -> remaining to request knockout mode if it makes sense based on the content type: - gtk/gtk_plotters.c: but I guess this needs testing by the GTK developers if this remains a good choice or not. - riscos/plotters.c - desktop/knockout.c: I believe its option_knockout needs to be 'true' because knockout_plot_start/knockout_plot_end needs to be called for each recursive html_redraw() call. - riscos/window.c: I'm a bit confused why there were tests on the content type which determine to additionally install the knockout plotter in front of the real plotter code as as far as I believe that only HTML content is profitable to be plotted in knockout mode, no ? Does this change make sense ? Anything which I'm overlooking here ? John. -- John Tytgat joty(a)netsurf-browser.org