[cairo] Dashed line issue with CAIRO_ANTIALIAS_NONE option

[Deokjin Kim]

Hello everyone,

When I use dashed line without antialias(AA), half is displayed as unbroken line and half is displayed as dashed line.
I used the latest cairo source code from git.(1.11.3)
And I set ctm matrix for scale.
(For reference, 1.10.2 also have similar issue. But phenomenon is slightly different.
For example, some portion is displayed thickly)

Below is my test code.
######################################################################
#include <cairo.h>
#include <stdio.h>
#include <sys/time.h>

int
main (int argc, char *argv[])
{
        cairo_surface_t *surface;
        cairo_t *cr;

        surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, 480, 480);
        cr = cairo_create (surface);

        double dashes[] = {1.0};
        int    ndash  = sizeof (dashes)/sizeof(dashes[0]);
        double offset = 1.0;
        cairo_matrix_t scale;
        scale.xy = scale.yx = 0.;
        scale.xx = scale.yy = 1.5037590265274048;
        scale.x0 = scale.y0 = 0.;

        cairo_set_matrix (cr, &scale);
        cairo_set_miter_limit (cr, 10.0);
        cairo_set_line_cap (cr, CAIRO_LINE_CAP_BUTT);
        cairo_set_line_join (cr, CAIRO_LINE_JOIN_MITER);
        cairo_set_antialias (cr, CAIRO_ANTIALIAS_NONE);

        cairo_set_dash (cr, dashes, ndash, offset);
        cairo_set_line_width (cr, 1.0);

        cairo_move_to (cr, 20, 20);
        cairo_line_to (cr, 480, 20);

        cairo_stroke (cr);

        /* Write output and clean up */
        cairo_surface_write_to_png (surface, "dash_test.png");
        cairo_destroy (cr);
        cairo_surface_destroy (surface);

        return 0;
}
######################################################################

Please give me a feedback.
Thank you in advance.

BR,
Deokjin Kim