1 files changed, 40 insertions, 0 deletions
diff --git a/include/libnsfb_plot_util.h b/include/libnsfb_plot_util.h
new file mode 100644
index 0000000..a1b0159
--- /dev/null
+++ b/include/libnsfb_plot_util.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2009 Vincent Sanders <vince@simtec.co.uk>
+ *
+ * This file is part of libnsfb, http://www.netsurf-browser.org/
+ * Licenced under the MIT License,
+ *                http://www.opensource.org/licenses/mit-license.php
+ *
+ * This is the exported interface for the libnsfb graphics library. 
+ */
+
+#ifndef _LIBNSFB_PLOT_UTIL_H
+#define _LIBNSFB_PLOT_UTIL_H 1
+
+
+/* alpha blend two pixels together */
+static inline nsfb_colour_t 
+nsfb_plot_ablend(nsfb_colour_t pixel, nsfb_colour_t scrpixel)
+{
+    int opacity = pixel >> 24;
+    int transp = 0x100 - opacity;
+    uint32_t rb, g;
+
+    rb = ((pixel & 0xFF00FF) * opacity +
+          (scrpixel & 0xFF00FF) * transp) >> 8;
+    g  = ((pixel & 0x00FF00) * opacity +
+          (scrpixel & 0x00FF00) * transp) >> 8;
+
+    return (rb & 0xFF00FF) | (g & 0xFF00);
+}
+
+
+bool nsfb_plot_clip(const nsfb_bbox_t * restrict clip, nsfb_bbox_t * restrict rect);
+
+bool nsfb_plot_clip_ctx(nsfb_t *nsfb, nsfb_bbox_t * restrict rect);
+
+bool nsfb_plot_clip_line(const nsfb_bbox_t * restrict clip, nsfb_bbox_t * restrict line);
+
+bool nsfb_plot_clip_line_ctx(nsfb_t *nsfb, nsfb_bbox_t * restrict line);
+
+#endif /* _LIBNSFB_PLOT_UTIL_H */