Add support for freetext annotations

This initial commit doesn't entirely complete the task:
1) There are a couple of ucs<->winansi conversions left out,
2) The text displayed by the appearance string can slightly
overflow the annotation rectangle.

3 files changed, 209 insertions, 3 deletions

diff --git a/source/pdf/pdf-annot.c b/source/pdf/pdf-annot.c
index c21a62d4..c0254756 100644
--- a/source/pdf/pdf-annot.c
+++ b/source/pdf/pdf-annot.c
@@ -926,3 +926,110 @@ pdf_set_ink_annot_list(pdf_document *doc, pdf_annot *annot, fz_point *pts, int *
 	for (i = 0; i < 3; i++)
 		pdf_array_push_drop(col, pdf_new_real(doc, color[i]));
 }
+
+static void find_free_font_name(pdf_obj *fdict, char *buf, int buf_size)
+{
+	int i;
+
+	/* Find a number X such that /FX doesn't occur as a key in fdict */
+	for (i = 0; 1; i++)
+	{
+		snprintf(buf, buf_size, "F%d", i);
+
+		if (!pdf_dict_gets(fdict, buf))
+			break;
+	}
+}
+
+void pdf_set_free_text_details(pdf_document *doc, pdf_annot *annot, fz_point *pos, char *text, char *font_name, float font_size, float color[3])
+{
+	fz_context *ctx = doc->ctx;
+	char nbuf[32];
+	pdf_obj *dr;
+	pdf_obj *form_fonts;
+	pdf_obj *font = NULL;
+	pdf_obj *ref;
+	pdf_font_desc *font_desc = NULL;
+	pdf_da_info da_info;
+	fz_buffer *fzbuf = NULL;
+	fz_matrix ctm;
+
+	fz_invert_matrix(&ctm, &annot->page->ctm);
+
+	dr = pdf_dict_gets(annot->page->me, "Resources");
+	if (!dr)
+	{
+		dr = pdf_new_dict(doc, 1);
+		pdf_dict_putp_drop(annot->page->me, "Resources", dr);
+	}
+
+	/* Ensure the resource dictionary includes a font dict */
+	form_fonts = pdf_dict_gets(dr, "Font");
+	if (!form_fonts)
+	{
+		form_fonts = pdf_new_dict(doc, 1);
+		pdf_dict_puts_drop(dr, "Font", form_fonts);
+		/* form_fonts is still valid if execution continues past the above call */
+	}
+
+	fz_var(fzbuf);
+	fz_var(font);
+	fz_try(ctx)
+	{
+		unsigned char *da_str;
+		int da_len;
+		fz_rect bounds;
+
+		find_free_font_name(form_fonts, nbuf, sizeof(nbuf));
+
+		font = pdf_new_dict(doc, 5);
+		ref = pdf_new_ref(doc, font);
+		pdf_dict_puts_drop(form_fonts, nbuf, ref);
+
+		pdf_dict_puts_drop(font, "Type", pdf_new_name(doc, "Font"));
+		pdf_dict_puts_drop(font, "Subtype", pdf_new_name(doc, "Type1"));
+		pdf_dict_puts_drop(font, "BaseFont", pdf_new_name(doc, font_name));
+		pdf_dict_puts_drop(font, "Encoding", pdf_new_name(doc, "WinAnsiEncoding"));
+
+		memcpy(da_info.col, color, sizeof(float)*3);
+		da_info.col_size = 3;
+		da_info.font_name = nbuf;
+		da_info.font_size = font_size;
+
+		fzbuf = fz_new_buffer(ctx, 0);
+		pdf_fzbuf_print_da(ctx, fzbuf, &da_info);
+
+		da_len = fz_buffer_storage(ctx, fzbuf, &da_str);
+		pdf_dict_puts_drop(annot->obj, "DA", pdf_new_string(doc, (char *)da_str, da_len));
+
+		/* FIXME: should convert to WinAnsiEncoding */
+		pdf_dict_puts_drop(annot->obj, "Contents", pdf_new_string(doc, text, strlen(text)));
+
+		font_desc = pdf_load_font(doc, NULL, font, 0);
+		pdf_measure_text(ctx, font_desc, (unsigned char *)text, strlen(text), &bounds);
+
+		bounds.x0 *= font_size;
+		bounds.x1 *= font_size;
+		bounds.y0 *= font_size;
+		bounds.y1 *= font_size;
+
+		bounds.x0 += pos->x;
+		bounds.x1 += pos->x;
+		bounds.y0 += pos->y;
+		bounds.y1 += pos->y;
+		fz_transform_rect(&bounds, &ctm);
+
+		pdf_dict_puts_drop(annot->obj, "Rect", pdf_new_rect(doc, &bounds));
+		update_rect(ctx, annot);
+	}
+	fz_always(ctx)
+	{
+		pdf_drop_obj(font);
+		fz_drop_buffer(ctx, fzbuf);
+		pdf_drop_font(ctx, font_desc);
+	}
+	fz_catch(ctx)
+	{
+		fz_rethrow(ctx);
+	}
+}
diff --git a/source/pdf/pdf-appearance.c b/source/pdf/pdf-appearance.c
index ffddddc6..e7c3190d 100644
--- a/source/pdf/pdf-appearance.c
+++ b/source/pdf/pdf-appearance.c
@@ -1,5 +1,9 @@
 #include "mupdf/pdf.h"
 
+#include <ft2build.h>
+#include FT_FREETYPE_H
+#include FT_ADVANCES_H
+
 #define MATRIX_COEFS (6)
 #define STRIKE_HEIGHT (0.375f)
 #define UNDERLINE_HEIGHT (0.075f)
@@ -1545,15 +1549,16 @@ void pdf_set_ink_appearance(pdf_document *doc, pdf_annot *annot)
 	fz_stroke_state *stroke = NULL;
 	fz_device *dev = NULL;
 	fz_display_list *strike_list = NULL;
+	fz_colorspace *cs = NULL;
 
 	fz_var(path);
 	fz_var(stroke);
 	fz_var(dev);
 	fz_var(strike_list);
+	fz_var(cs);
 	fz_try(ctx)
 	{
 		fz_rect rect = fz_empty_rect;
-		fz_colorspace *cs;
 		float color[4];
 		float width;
 		pdf_obj *list;
@@ -1622,6 +1627,7 @@ void pdf_set_ink_appearance(pdf_document *doc, pdf_annot *annot)
 	}
 	fz_always(ctx)
 	{
+		fz_drop_colorspace(ctx, cs);
 		fz_free_device(dev);
 		fz_drop_stroke_state(ctx, stroke);
 		fz_free_path(ctx, path);
@@ -1632,3 +1638,95 @@ void pdf_set_ink_appearance(pdf_document *doc, pdf_annot *annot)
 		fz_rethrow(ctx);
 	}
 }
+
+static fz_text *layout_text(fz_context *ctx, font_info *font_rec, char *str, float x, float y)
+{
+	fz_matrix tm;
+	fz_font *font = font_rec->font->font;
+	fz_text *text;
+	int mask = FT_LOAD_NO_SCALE | FT_LOAD_IGNORE_TRANSFORM;
+
+	fz_scale(&tm, font_rec->da_rec.font_size, font_rec->da_rec.font_size);
+	text = fz_new_text(ctx, font, &tm, 0);
+
+	fz_try(ctx)
+	{
+
+		while (*str)
+		{
+			FT_Fixed adv;
+
+			/* FIXME: convert str from utf8 to WinAnsi */
+			int gid = FT_Get_Char_Index(font->ft_face, *str);
+			fz_add_text(ctx, text, gid, *str, x, y);
+
+			FT_Get_Advance(font->ft_face, gid, mask, &adv);
+			x += ((float)adv) * font_rec->da_rec.font_size / ((FT_Face)font->ft_face)->units_per_EM;
+
+			str++;
+		}
+	}
+	fz_catch(ctx)
+	{
+		fz_free_text(ctx, text);
+		fz_rethrow(ctx);
+	}
+
+	return text;
+}
+
+void pdf_update_free_text_annot_appearance(pdf_document *doc, pdf_annot *annot)
+{
+	fz_context *ctx = doc->ctx;
+	const fz_matrix *page_ctm = &annot->page->ctm;
+	pdf_obj *obj = annot->obj;
+	pdf_obj *dr = pdf_dict_getp(annot->page->me, "Resources");
+	fz_display_list *dlist = NULL;
+	fz_device *dev = NULL;
+	font_info font_rec;
+	fz_text *text = NULL;
+	fz_colorspace *cs = NULL;
+
+	memset(&font_rec, 0, sizeof(font_rec));
+
+	fz_var(dlist);
+	fz_var(dev);
+	fz_var(text);
+	fz_var(cs);
+	fz_try(ctx)
+	{
+		char *contents = pdf_to_str_buf(pdf_dict_gets(obj, "Contents"));
+		char *da = pdf_to_str_buf(pdf_dict_gets(obj, "DA"));
+		fz_rect rect = annot->rect;
+
+		get_font_info(doc, dr, da, &font_rec);
+
+		switch (font_rec.da_rec.col_size)
+		{
+		case 1: cs = fz_device_gray(doc->ctx); break;
+		case 3: cs = fz_device_rgb(doc->ctx); break;
+		case 4: cs = fz_device_cmyk(doc->ctx); break;
+		}
+
+		fz_transform_rect(&rect, page_ctm);
+		text = layout_text(ctx, &font_rec, contents, rect.x0, rect.y0);
+
+		dlist = fz_new_display_list(ctx);
+		dev = fz_new_list_device(ctx, dlist);
+		fz_fill_text(dev, text, page_ctm, cs, font_rec.da_rec.col, 1.0f);
+
+		pdf_set_annot_appearance(doc, annot, &annot->rect, dlist);
+	}
+	fz_always(ctx)
+	{
+		fz_free_device(dev);
+		fz_drop_display_list(ctx, dlist);
+		font_info_fin(ctx, &font_rec);
+		fz_free_text(ctx, text);
+		fz_drop_colorspace(ctx, cs);
+	}
+	fz_catch(ctx)
+	{
+		fz_rethrow(ctx);
+	}
+}
diff --git a/source/pdf/pdf-form.c b/source/pdf/pdf-form.c
index f6e2f721..1ba2cd82 100644
--- a/source/pdf/pdf-form.c
+++ b/source/pdf/pdf-form.c
@@ -1,7 +1,5 @@
 #include "mupdf/pdf.h"
 
-#define SMALL_FLOAT (0.00001)
-
 enum
 {
 	F_Invisible = 1 << (1-1),
@@ -474,6 +472,9 @@ void pdf_update_appearance(pdf_document *doc, pdf_annot *annot)
 				break;
 			}
 			break;
+		case FZ_ANNOT_FREETEXT:
+			pdf_update_free_text_annot_appearance(doc, annot);
+			break;
 		case FZ_ANNOT_STRIKEOUT:
 		case FZ_ANNOT_UNDERLINE:
 		case FZ_ANNOT_HIGHLIGHT: