From 3357d32ec4b39d4cee88b0f46157c01bd39f61aa Mon Sep 17 00:00:00 2001
From: Aaron van Geffen <aaron@aaronweb.net>
Date: Fri, 22 Sep 2017 12:41:46 +0200
Subject: [PATCH] Port TTF_RenderUTF8_Shaded and TTF_drawLine_Shaded from
 SDL_ttf.

---
 src/openrct2/drawing/ttf.h         |   1 +
 src/openrct2/drawing/ttf_sdlport.c | 161 +++++++++++++++++++++++++++++
 2 files changed, 162 insertions(+)

diff --git a/src/openrct2/drawing/ttf.h b/src/openrct2/drawing/ttf.h
index adc3046134..46c39a8634 100644
--- a/src/openrct2/drawing/ttf.h
+++ b/src/openrct2/drawing/ttf.h
@@ -54,6 +54,7 @@ TTF_Font * TTF_OpenFont(const char *file, int ptsize);
 int TTF_GlyphIsProvided(const TTF_Font *font, codepoint_t ch);
 int TTF_SizeUTF8(TTF_Font *font, const char *text, int *w, int *h);
 TTFSurface * TTF_RenderUTF8_Solid(TTF_Font *font, const char *text, uint32 colour);
+TTFSurface * TTF_RenderUTF8_Shaded(TTF_Font *font, const char *text, uint32 fg, uint32 bg);
 void TTF_CloseFont(TTF_Font *font);
 void TTF_Quit(void);
 
diff --git a/src/openrct2/drawing/ttf_sdlport.c b/src/openrct2/drawing/ttf_sdlport.c
index 5dc5c8f7e1..1ad66919b8 100644
--- a/src/openrct2/drawing/ttf_sdlport.c
+++ b/src/openrct2/drawing/ttf_sdlport.c
@@ -262,6 +262,27 @@ static void TTF_drawLine_Solid(const TTF_Font *font, const TTFSurface *textbuf,
     }
 }
 
+/* Draw a shaded line of underline_height (+ optional outline)
+   at the given row. The row value must take the
+   outline into account.
+*/
+static void TTF_drawLine_Shaded(const TTF_Font *font, const TTFSurface *textbuf, const int row)
+{
+    int line;
+    uint8 *dst_check = (uint8*) textbuf->pixels + textbuf->pitch * textbuf->h;
+    uint8 *dst;
+    int height;
+
+    TTF_initLineMectrics(font, textbuf, row, &dst, &height);
+
+    /* Draw line */
+    for (line=height; line>0 && dst < dst_check; --line)
+    {
+        memset(dst, NUM_GRAYS - 1, textbuf->w);
+        dst += textbuf->pitch;
+    }
+}
+
 static void TTF_SetFTError(const char *msg, FT_Error error)
 {
 #ifdef USE_FREETYPE_ERRORS
@@ -1261,6 +1282,146 @@ TTFSurface *TTF_RenderUTF8_Solid(TTF_Font *font,
     return textbuf;
 }
 
+TTFSurface *TTF_RenderUTF8_Shaded(TTF_Font *font,
+                const char *text, uint32 fg, uint32 bg)
+{
+    bool first;
+    int xstart;
+    int width;
+    int height;
+    TTFSurface* textbuf;
+    uint8* src;
+    uint8* dst;
+    uint8* dst_check;
+    int row, col;
+    FT_Bitmap* current;
+    c_glyph *glyph;
+    FT_Error error;
+    FT_Long use_kerning;
+    FT_UInt prev_index = 0;
+    size_t textlen;
+
+    TTF_CHECKPOINTER(text, NULL);
+
+    /* Get the dimensions of the text surface */
+    if ((TTF_SizeUTF8(font, text, &width, &height) < 0 ) || !width)
+    {
+        TTF_SetError("Text has zero width");
+        return NULL;
+    }
+
+    /* Create the target surface */
+    textbuf = calloc(1, sizeof(TTFSurface));
+    if (textbuf == NULL)
+    {
+        return NULL;
+    }
+    textbuf->w = width;
+    textbuf->h = height;
+    textbuf->pitch = width;
+    textbuf->pixels = calloc(1, width * height);
+
+    /* Adding bound checking to avoid all kinds of memory corruption errors
+       that may occur. */
+    dst_check = (uint8*) textbuf->pixels + textbuf->pitch * textbuf->h;
+
+    /* check kerning */
+    use_kerning = FT_HAS_KERNING(font->face) && font->kerning;
+
+    /* Load and render each character */
+    textlen = strlen(text);
+    first = true;
+    xstart = 0;
+    while (textlen > 0)
+    {
+        uint16 c = UTF8_getch(&text, &textlen);
+        if (c == UNICODE_BOM_NATIVE || c == UNICODE_BOM_SWAPPED)
+        {
+            continue;
+        }
+
+        error = Find_Glyph(font, c, CACHED_METRICS|CACHED_PIXMAP);
+        if (error)
+        {
+            TTF_SetFTError("Couldn't find glyph", error);
+            ttf_free_surface(textbuf);
+            return NULL;
+        }
+
+        glyph = font->current;
+
+        /* Ensure the width of the pixmap is correct. On some cases,
+         * freetype may report a larger pixmap than possible.*/
+        width = glyph->pixmap.width;
+        if (font->outline <= 0 && width > glyph->maxx - glyph->minx)
+        {
+            width = glyph->maxx - glyph->minx;
+        }
+
+        /* do kerning, if possible AC-Patch */
+        if (use_kerning && prev_index && glyph->index)
+        {
+            FT_Vector delta;
+            FT_Get_Kerning(font->face, prev_index, glyph->index, ft_kerning_default, &delta);
+            xstart += delta.x >> 6;
+        }
+
+        /* Compensate for the wrap around with negative minx's */
+        if (first && (glyph->minx < 0))
+        {
+            xstart -= glyph->minx;
+        }
+        first = false;
+
+        current = &glyph->pixmap;
+        for (row = 0; row < current->rows; ++row)
+        {
+            /* Make sure we don't go either over, or under the
+             * limit */
+            if (row + glyph->yoffset < 0)
+            {
+                continue;
+            }
+            if (row + glyph->yoffset >= textbuf->h)
+            {
+                continue;
+            }
+
+            dst = (uint8*) textbuf->pixels +
+                (row+glyph->yoffset) * textbuf->pitch +
+                xstart + glyph->minx;
+            src = current->buffer + row * current->pitch;
+
+            for (col=width; col>0 && dst < dst_check; --col)
+            {
+                *dst++ |= *src++;
+            }
+        }
+
+        xstart += glyph->advance;
+        if (TTF_HANDLE_STYLE_BOLD(font))
+        {
+            xstart += font->glyph_overhang;
+        }
+        prev_index = glyph->index;
+    }
+
+    /* Handle the underline style */
+    if (TTF_HANDLE_STYLE_UNDERLINE(font))
+    {
+        row = TTF_underline_top_row(font);
+        TTF_drawLine_Shaded(font, textbuf, row);
+    }
+
+    /* Handle the strikethrough style */
+    if (TTF_HANDLE_STYLE_STRIKETHROUGH(font))
+    {
+        row = TTF_strikethrough_top_row(font);
+        TTF_drawLine_Shaded(font, textbuf, row);
+    }
+    return textbuf;
+}
+
 static bool CharacterIsDelimiter(char c, const char *delimiters)
 {
     while (*delimiters) {