Fix drawing issues (there is still some left)

Signed-off-by: Mattias Andrée <maandree@kth.se>

6 files changed, 114 insertions, 51 deletions

diff --git a/Makefile b/Makefile
index dd440d0..4c70752 100644
--- a/Makefile
+++ b/Makefile
@@ -8,6 +8,7 @@ OBJ =\
 	libskrift_calculate_dpi.o\
 	libskrift_close_font.o\
 	libskrift_create_context.o\
+	libskrift_draw_text.o\
 	libskrift_format_settings.o\
 	libskrift_free_context.o\
 	libskrift_get_grapheme_glyph.o\
diff --git a/demo.c b/demo.c
index 9157a5c..062f515 100644
--- a/demo.c
+++ b/demo.c
@@ -11,13 +11,14 @@ main(void)
 {
 	LIBSKRIFT_FONT *font;
 	LIBSKRIFT_CONTEXT *ctx;
-	struct libskrift_glyph *glyph;
+	struct libskrift_image image = {LIBSKRIFT_R8G8B8A8, LIBSKRIFT_HOST_SUBPIXEL, 0, 800, 600, NULL, NULL, NULL};
 	struct libskrift_rendering rendering = LIBSKRIFT_DEFAULT_RENDERING;
-	uint16_t i, x, y;
+	struct libskrift_colour colour = LIBSKRIFT_PREMULTIPLY(1, 1, .80f, .50f, .20f);
 	double height;
+	size_t size, i;
 
 	rendering.smoothing      = LIBSKRIFT_SUBPIXEL;
-	rendering.subpixel_order = LIBSKRIFT_RGB;
+	rendering.subpixel_order = LIBSKRIFT_NONE;
 	rendering.flags          = 0;
 
 	if (libskrift_open_font_file(&font, DEMO_FONT)) {
@@ -31,43 +32,37 @@ main(void)
 	}
 	libskrift_close_font(font);
 
-#if 1
-	if (libskrift_get_cluster_glyph(ctx, "x̴̑", NULL, 0, 0, &glyph) < 0) {
-		perror("libskrift_get_cluster_glyph");
+	size = 4;
+	size *= (size_t)image.width;
+	size *= (size_t)image.height;
+	image.image = malloc(size);
+	if (!image.image) {
+		perror("malloc");
 		return -1;
 	}
-#else
-	if (libskrift_get_grapheme_glyph(ctx, 197 /* Å */, 0, 0, &glyph)) {
-		perror("libskrift_get_grapheme_glyph");
-		return -1;
+	for (i = 0; i < size; i += 4) {
+		((uint8_t *)image.image)[i + 0] = 32U;
+		((uint8_t *)image.image)[i + 1] = 48U;
+		((uint8_t *)image.image)[i + 2] = 64U;
+		((uint8_t *)image.image)[i + 3] = 192U;
 	}
-#endif
 
-	if (rendering.smoothing == LIBSKRIFT_GREYSCALE) {
-		printf("P2\n%u %u\n255\n", glyph->width, glyph->height);
-		printf("# x-position: %i\n",  glyph->x);
-		printf("# y-position: %i\n",  glyph->y);
-		printf("# advance:    %lf\n", glyph->advance);
-		for (i = y = 0; y < glyph->height; y++) {
-			for (x = 0; x < glyph->width; x++, i++)
-				printf("%3u ", glyph->image[i]);
-			printf("\n\n");
-		}
-		fflush(stdout);
-	} else {
-		printf("P3\n%u %u\n255\n", glyph->width, glyph->height);
-		printf("# x-position: %i\n",  glyph->x);
-		printf("# y-position: %i\n",  glyph->y);
-		printf("# advance:    %lf\n", glyph->advance);
-		for (i = y = 0; y < glyph->height; y++) {
-			for (x = 0; x < glyph->width * 3; x++, i++)
-				printf("%3u ", glyph->image[i]);
-			printf("\n\n");
-		}
-		fflush(stdout);
+	if (libskrift_draw_text(ctx, "hello world", &colour, 0, 300, &image) < 0) {
+		perror("libskrift_draw_text");
+		return -1;
 	}
 
-	free(glyph);
+	printf("P7\n");
+	printf("WIDTH %u\n", image.width);
+	printf("HEIGHT %u\n", image.height);
+	printf("DEPTH 4\n");
+	printf("MAXVAL 255\n");
+	printf("TUPLTYPE RGB_ALPHA\n");
+	printf("ENDHDR\n");
+	fwrite(image.image, 1, size, stdout);
+	fflush(stdout);
+
+	free(image.image);
 	libskrift_free_context(ctx);
 	return 0;
 }
diff --git a/libskrift.h b/libskrift.h
index 93adb79..aeeaad2 100644
--- a/libskrift.h
+++ b/libskrift.h
@@ -184,6 +184,13 @@ struct libskrift_colour {
 
 #define LIBSKRIFT_NO_SAVED_GRAPHEME {0, 0}
 
+#define LIBSKRIFT_PREMULTIPLY(OPACITY, ALPHA, RED, GREEN, BLUE)\
+	{(OPACITY),\
+	 (ALPHA) * (OPACITY),\
+	 (RED)   * (ALPHA) * (OPACITY),\
+	 (GREEN) * (ALPHA) * (OPACITY),\
+	 (BLUE)  * (ALPHA) * (OPACITY)}
+
 
 _LIBSKRIFT_GCC_ONLY(__attribute__((__const__, __warn_unused_result__)))
 inline double
@@ -253,6 +260,10 @@ _LIBSKRIFT_GCC_ONLY(__attribute__((__nonnull__(1, 2, 6))))
 int libskrift_apply_glyph(LIBSKRIFT_CONTEXT *, const struct libskrift_glyph *, const struct libskrift_colour *,
                           int16_t, int16_t, struct libskrift_image *);
 
+_LIBSKRIFT_GCC_ONLY(__attribute__((__nonnull__(1, 2, 6))))
+int libskrift_draw_text(LIBSKRIFT_CONTEXT *, const char *, const struct libskrift_colour *,
+                        int16_t, int16_t, struct libskrift_image *);
+
 
 _LIBSKRIFT_GCC_ONLY(__attribute__((__nonnull__)))
 void libskrift_srgb_preprocess(struct libskrift_image *, size_t, size_t, size_t, size_t);
diff --git a/libskrift_apply_glyph.c b/libskrift_apply_glyph.c
index 05770ce..85e4bd2 100644
--- a/libskrift_apply_glyph.c
+++ b/libskrift_apply_glyph.c
@@ -45,10 +45,10 @@ libskrift_apply_glyph(LIBSKRIFT_CONTEXT *ctx, const struct libskrift_glyph *glyp
 	size_t img_linesize, gly_linesize, i, gly_psize, usize;
 	size_t ri, gi, bi, rj, gj, bj;
 	uint16_t x1, y1, x2, y2;
-	int16_t sx2, sy2;
+	int16_t sx1, sy1, sx2, sy2;
 	uint8_t high;
 	uint8_t *img, *img_start = image->image;
-	const uint8_t *gly = glyph->image;
+	const uint8_t *gly = glyph->image, *gly_start;
 	const uint16_t u16 = 0x0102;
 	const uint32_t u32 = 0x01020304L;
 	const uint64_t u64 = 0x0102030405060708LL;
@@ -69,30 +69,42 @@ libskrift_apply_glyph(LIBSKRIFT_CONTEXT *ctx, const struct libskrift_glyph *glyp
 		return -1;
 	}
 
-	/* Drawing area on image */
-	sx2 = (int16_t)(x + (int16_t)glyph->width);
-	sy2 = (int16_t)(y + (int16_t)glyph->height);
-	x1 = x < 0 ? 0 : (uint16_t)x;
-	y1 = y < 0 ? 0 : (uint16_t)y;
-	if (sx2 <= 0 || sy2 <= 0 || x1 >= image->width || y1 >= image->height)
+	/* Top left corner of glyph on image */
+	sx1 = (int16_t)(x + glyph->x);
+	sy1 = (int16_t)(y + glyph->y);
+
+	/* Post-bottom right corner of glyph on image */
+	sx2 = (int16_t)(sx1 + (int16_t)glyph->width);
+	sy2 = (int16_t)(sy1 + (int16_t)glyph->height);
+	if (sx2 <= 0 || sy2 <= 0)
+		return 0;
+
+	/* First pixel in image to draw on */
+	x1 = sx1 < 0 ? 0 : (uint16_t)sx1;
+	y1 = sy1 < 0 ? 0 : (uint16_t)sy1;
+	if (x1 >= image->width || y1 >= image->height)
 		return 0;
+
+	/* Post-last pixel in image to draw on */
+	sx2 = (int16_t)(sx1 + (int16_t)glyph->width);
+	sy2 = (int16_t)(sy1 + (int16_t)glyph->height);
 	x2 = (uint16_t)sx2 < image->width  ? (uint16_t)sx2 : image->width;
 	y2 = (uint16_t)sy2 < image->height ? (uint16_t)sy2 : image->height;
-	sx2 = (int16_t)x2;
-	sy2 = (int16_t)y2;
 
-	/* Drawing area on glyph */
-	startc = x <= 0 ? 0 : (size_t)-x;
-	startr = y <= 0 ? 0 : (size_t)-y;
-	endc = x2 < image->width  ? glyph->width  : (uint16_t)(sx2 - x);
-	endr = y2 < image->height ? glyph->height : (uint16_t)(sy2 - y);
+	/* First pixel in glyph to draw */
+	startc = (uint16_t)((int16_t)x1 - sx1);
+	startr = (uint16_t)((int16_t)y1 - sy1);
+
+	/* Post-last pixel in glyph to draw*/
+	endc = (uint16_t)((int16_t)x2 - sx1);
+	endr = (uint16_t)((int16_t)y2 - sy1);
 
 	img_linesize = (size_t)image->width * psize;
 	img_start += (size_t)y1 * img_linesize;
 	img_start += (size_t)x1 * psize;
 
-	gly_psize = ctx->rendering.smoothing ? 3 : 1;
-	gly_linesize = (size_t)image->width * gly_psize;
+	gly_psize = (ctx->rendering.smoothing == LIBSKRIFT_SUBPIXEL) ? 3 : 1;
+	gly_linesize = (size_t)glyph->width * gly_psize;
 	gly += startr * gly_linesize;
 
 	usize = image->endian >= LIBSKRIFT_HOST_SUBPIXEL ? settings.spsize : psize;
@@ -180,6 +192,7 @@ libskrift_apply_glyph(LIBSKRIFT_CONTEXT *ctx, const struct libskrift_glyph *glyp
 		rj = (size_t)settings.rpos * settings.spsize;
 		gj = (size_t)settings.gpos * settings.spsize;
 		bj = (size_t)settings.bpos * settings.spsize;
+		gly_start = gly;
 		for (img = img_start, r = startr; r < endr; r++, img += img_linesize, gly += gly_linesize) {
 			for (c = startc, i = 0; c < endc; c += gly_psize, i += psize) {
 				img[i + rj] ^= gly[c + ri];
@@ -191,6 +204,7 @@ libskrift_apply_glyph(LIBSKRIFT_CONTEXT *ctx, const struct libskrift_glyph *glyp
 			ri = rj + j;
 			gi = gj + j;
 			bi = bj + j;
+			gly = gly_start;
 			for (img = img_start, r = startr; r < endr; r++, img += img_linesize, gly += gly_linesize) {
 				for (c = startc, i = 0; c < endc; c += gly_psize, i += psize) {
 					img[i + ri] = img[i + rj];
diff --git a/libskrift_draw_text.c b/libskrift_draw_text.c
new file mode 100644
index 0000000..8f46df4
--- /dev/null
+++ b/libskrift_draw_text.c
@@ -0,0 +1,27 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+int
+libskrift_draw_text(LIBSKRIFT_CONTEXT *ctx, const char *text, const struct libskrift_colour *colour,
+                    int16_t x, int16_t y, struct libskrift_image *image)
+{
+	struct libskrift_saved_grapheme saved = LIBSKRIFT_NO_SAVED_GRAPHEME;
+	struct libskrift_glyph *glyph;
+	double xpos = 0;
+	ssize_t len;
+	int r;
+
+	for (; *text; text += len) {
+		len = libskrift_get_cluster_glyph(ctx, text, &saved, xpos, 0, &glyph);
+		if (len < 0)
+			return -1;
+
+		r = libskrift_apply_glyph(ctx, glyph, colour, x, y, image);
+		xpos += glyph->advance;
+		free(glyph);
+		if (r)
+			return -1;
+	}
+
+	return 0;
+}
diff --git a/libskrift_merge_glyphs.c b/libskrift_merge_glyphs.c
index 6c62fc8..4df6f7a 100644
--- a/libskrift_merge_glyphs.c
+++ b/libskrift_merge_glyphs.c
@@ -10,9 +10,24 @@ libskrift_merge_glyphs(LIBSKRIFT_CONTEXT *ctx, const struct libskrift_glyph *gly
 	int16_t x1a, x1b, x2a, x2b, y1a, y1b, y2a, y2b, x1, x2, y1, y2;
 	size_t width, height, r, c, size, psize;
 	size_t src_off, dest_off, src_linesize, dest_linesize;
+	const struct libskrift_glyph *t;
 
 	psize = ctx->rendering.smoothing ? 3 : 1;
 
+	if (!(glyph1->width | glyph1->height)) {
+		t = glyph1;
+		glyph1 = glyph2;
+		glyph2 = t;
+	}
+	if (!(glyph2->width | glyph2->height)) {
+		size = offsetof(struct libskrift_glyph, image) + glyph1->size;
+		*glyphp = calloc(1, size);
+		if (!*glyphp)
+			return -1;
+		memcpy(*glyphp, glyph1, size);
+		return 0;
+	}
+
 	x1a = glyph1->x;
 	x1b = glyph2->x;
 	y1a = glyph1->y;