Add a test case for commit d07fb410568423

Signed-off-by: Uli Schlachter <psychon@znc.in>

1 files changed, 136 insertions, 0 deletions

diff --git a/test/record-write-png.c b/test/record-write-png.c
new file mode 100644
index 000000000..da0e253bd
--- /dev/null
+++ b/test/record-write-png.c
@@ -0,0 +1,136 @@
+/*
+ * Copyright © 2021 Matthias Clasen
+ * Copyright © 2021 Uli Schlachter
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of
+ * Red Hat, Inc. not be used in advertising or publicity pertaining to
+ * distribution of the software without specific, written prior
+ * permission. Red Hat, Inc. makes no representations about the
+ * suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * RED HAT, INC. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL RED HAT, INC. BE LIABLE FOR ANY SPECIAL,
+ * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+ * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+ * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Authors:
+ *	Matthias Clasen
+ *	Uli Schlachter
+ */
+
+// Test case for https://gitlab.freedesktop.org/cairo/cairo/-/merge_requests/118
+// A recording surface with a non-zero origin gets cut off when passed to
+// cairo_surface_write_to_png().
+
+#include "cairo-test.h"
+
+#include <assert.h>
+
+struct buffer {
+    char *data;
+    size_t length;
+};
+
+static cairo_surface_t *
+prepare_recording (void)
+{
+    cairo_surface_t *surface;
+    cairo_rectangle_t rect;
+    cairo_t *cr;
+
+    rect.x = -1;
+    rect.y = -2;
+    rect.width = 3;
+    rect.height = 4;
+    surface = cairo_recording_surface_create (CAIRO_CONTENT_COLOR_ALPHA, &rect);
+
+    cr = cairo_create (surface);
+    cairo_set_line_width (cr, 1);
+    cairo_set_source_rgb (cr, 1, 1, 1);
+    cairo_rectangle (cr, 0.5, -0.5, 1., 1.);
+    cairo_stroke (cr);
+    cairo_destroy (cr);
+
+    return surface;
+}
+
+static cairo_status_t
+write_callback (void *closure, const unsigned char *data, unsigned int length)
+{
+    struct buffer *buffer = closure;
+
+    buffer->data = realloc (buffer->data, buffer->length + length);
+    memcpy (&buffer->data[buffer->length], data, length);
+    buffer->length += length;
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+static cairo_status_t
+read_callback (void *closure, unsigned char *data, unsigned int length)
+{
+    struct buffer *buffer = closure;
+
+    assert (buffer->length >= length);
+    memcpy (data, buffer->data, length);
+    buffer->data += length;
+    buffer->length -= length;
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+static cairo_surface_t *
+png_round_trip (cairo_surface_t *input_surface)
+{
+    cairo_surface_t *output_surface;
+    struct buffer buffer;
+    void *to_free;
+
+    // Turn the surface into a PNG
+    buffer.data = NULL;
+    buffer.length = 0;
+    cairo_surface_write_to_png_stream (input_surface, write_callback, &buffer);
+    to_free = buffer.data;
+
+    // Load the PNG again
+    output_surface = cairo_image_surface_create_from_png_stream (read_callback, &buffer);
+
+    free (to_free);
+    return output_surface;
+}
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    cairo_surface_t *recording, *surface;
+
+    // Draw a black background so that the output does not vary with alpha
+    cairo_set_source_rgb (cr, 0, 0, 0);
+    cairo_paint (cr);
+
+    recording = prepare_recording ();
+    surface = png_round_trip (recording);
+
+    cairo_set_source_surface (cr, surface, 0, 0);
+    cairo_paint (cr);
+
+    cairo_surface_destroy (recording);
+    cairo_surface_destroy (surface);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+CAIRO_TEST (record_write_png,
+	    "Test writing to png with non-zero origin",
+	    "record, transform", /* keywords */
+	    NULL, /* requirements */
+	    4, 4,
+	    NULL, draw)