Commit baad14ee authored by Committed by Tor Lillqvist
Improve and simplify line segment rendering on Win32, especially the
2005-06-23 Tor Lillqvist <firstname.lastname@example.org> Improve and simplify line segment rendering on Win32, especially the implementation of GDK_CAP_NOT_LAST, and dashed lines. Fixes bug #306396. * gdk/win32/gdkprivate-win32.h (GdkGCWin32): Save the GdkGC's line_style, cap_style and join_style as such in the GdkGCWin32. Don't need to keep the pen_double_dash flag, we can check the line_style. * gdk/win32/gdkgc-win32.c (fixup_pen): New internal function. Sets up the GDI pen type, style, end cap and join attributes to use based on the pen width, GDK line style, end cap style, and join style. For a narrow (zero-width) GDK pen with the GDK_CAP_NOT_LAST end cap style, which typically are used for XOR drawing where it is essential that the last pixel is not drawn, use a GDI cosmetic pen. Only for a cosmetic pen does GDI not draw the last pixel. I deduced this by experimetation, the documentation is rather vague. For other GDK pens use a geometric GDI pen. If the width is 0 or 1 and the GDK end cap style is GDK_CAP_BUTT, and the line style is GDK_LINE_SOLID, use PS_ENDCAP_ROUND. This ensures that also single-pixel length lines are drawn. (For sngle-pixel width lines roundness as such is of course irrelevant.) For dashed lines, use PS_ENDCAP_FLAT. For wide lines use PS_ENDCAP_FLAT, _ROUND or _SQUARE, respectively, for GDK_CAP_BUTT, GDK_CAP_ROUND and GDK_CAP_PROJECTING. For one pixel on-off dashed lines, use PS_ALTERNATE, it seems to work better than PS_USERSTYLE. For other dashed lines, use PS_USERSTYLE and the dashes as set by the user (or the default four-pixel on-off style). (gdk_win32_gc_values_to_win32values, gdk_win32_gc_set_dashes): Call fixup_pen() to do the pen settings after modifying some of the GDK GC attributes that affect pens. * gdk/win32/gdkdrawable-win32.c (render_line_horizontal, render_line_vertical, draw_segments): Check GdkGCWin32::line_style instead of the the removed pen_double_dash member. Don't use PATCOPY unconditionally in the PatBlt() call, use a raster ope code that depends on the GC function in use. (draw_rectangle, draw_segments, draw_lines): Be more careful in deciding when to do the manual dash rendering. (draw_segments): Don't do any manual "last point" drawing at all. The above changes takes care of narrow line segments being drawn correctly in most cases, at least on NT-based Windows.
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