[devel] Implement expansion to 16 bits
diff --git a/pngvalid.c b/pngvalid.c
index 417d71b..ff78b22 100644
--- a/pngvalid.c
+++ b/pngvalid.c
@@ -4465,6 +4465,48 @@
}
IT(expand_gray_1_2_4_to_8, expand);
+/* png_set_expand_16 */
+static void
+image_transform_png_set_expand_16_set(PNG_CONST image_transform *this,
+ transform_display *that, png_structp pp, png_infop pi)
+{
+ png_set_expand_16(pp);
+ this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_expand_16_mod(PNG_CONST image_transform *this,
+ image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+ /* Expect expand_16 to expand everything to 16 bits as a result of also
+ * causing 'expand' to happen.
+ */
+ if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+ image_pixel_convert_PLTE(that, &display->this);
+
+ if (that->have_tRNS)
+ image_pixel_add_alpha(that, &display->this);
+
+ if (that->bit_depth < 16)
+ that->sample_depth = that->bit_depth = 16;
+
+ this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_expand_16_add(image_transform *this,
+ PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+ UNUSED(colour_type)
+
+ this->next = *that;
+ *that = this;
+
+ /* expand_16 does something unless the bit depth is already 16. */
+ return bit_depth < 16;
+}
+
+IT(expand_16, expand_gray_1_2_4_to_8);
/* png_set_strip_16 */
static void
@@ -4516,7 +4558,7 @@
return bit_depth > 8;
}
-IT(strip_16, expand_gray_1_2_4_to_8);
+IT(strip_16, expand_16);
/* png_set_strip_alpha */
static void
