Add mgl_text_set_max_width and mgl_text_set_max_rows

3 files changed, 92 insertions, 68 deletions

diff --git a/include/mgl/graphics/text.h b/include/mgl/graphics/text.h
index 89ae541..4dd0219 100644
--- a/include/mgl/graphics/text.h
+++ b/include/mgl/graphics/text.h
@@ -23,6 +23,8 @@ typedef struct {
     mgl_vec2f position;
     mgl_vec2f bounds;
     bool bounds_dirty;
+    float max_width;
+    unsigned int max_rows;
 } mgl_text;
 
 /*
@@ -41,6 +43,10 @@ void mgl_text_set_string(mgl_text *self, const char *str, size_t str_size);
 void mgl_text_set_font(mgl_text *self, mgl_font *font);
 void mgl_text_set_position(mgl_text *self, mgl_vec2f position);
 void mgl_text_set_color(mgl_text *self, mgl_color color);
+/* If |max_width| is 0 then the text has no max width */
+void mgl_text_set_max_width(mgl_text *self, float max_width);
+/* If |max_rows| is 0 then the text can display an unlimited amount of rows */
+void mgl_text_set_max_rows(mgl_text *self, unsigned int max_rows);
 mgl_vec2f mgl_text_get_bounds(mgl_text *self);
 /* Returns the position of the character on the screen (relative to the current mgl_view) */
 mgl_vec2f mgl_text_find_character_pos(mgl_text *self, size_t index);
diff --git a/src/graphics/text.c b/src/graphics/text.c
index f84169a..89994c5 100644
--- a/src/graphics/text.c
+++ b/src/graphics/text.c
@@ -9,15 +9,38 @@
 
 #define TAB_WIDTH 4
 
+typedef struct {
+    size_t codepoint_index;
+    uint32_t codepoint;
+    float kerning;
+    float glyph_width;
+    const mgl_font_glyph *glyph;
+    mgl_vec2f glyph_offset;
+} codepoint_loop_callback_data;
+
+static float max_float(float a, float b) {
+    return a >= b ? a : b;
+}
+
+static float float_abs(float value) {
+    return value >= 0.0f ? value : -value;
+}
+
 /* Return false to stop the loop. |glyph| is not valid if codepoint is '\n' */
-typedef bool (*codepoint_loop_callback)(size_t codepoint_index, uint32_t codepoint, const mgl_font_glyph *glyph, void *userdata);
+typedef bool (*codepoint_loop_callback)(codepoint_loop_callback_data callback_data, void *userdata);
 static void mgl_text_for_each_codepoint(const mgl_text *self, codepoint_loop_callback callback, void *userdata) {
     mgl_font_glyph glyph;
     size_t codepoint_index = 0;
+    float kerning = 0.0f;
+    float glyph_width = 0.0f;
+    uint32_t prev_codepoint = 0;
+    mgl_vec2f glyph_offset = {0, 0};
+    unsigned int rows = 0;
+
     for(size_t i = 0; i < self->text_size;) {
         unsigned char *cp = (unsigned char*)&self->text[i];
-        uint32_t codepoint;
-        size_t clen;
+        uint32_t codepoint = 0;
+        size_t clen = 0;
         if(!mgl_utf8_decode(cp, self->text_size - i, &codepoint, &clen)) {
             codepoint = *cp;
             clen = 1;
@@ -25,52 +48,59 @@ static void mgl_text_for_each_codepoint(const mgl_text *self, codepoint_loop_cal
 
         if(codepoint == '\t') {
             if(mgl_font_get_glyph(self->font, ' ', &glyph) == 0) {
-                if(!callback(codepoint_index, codepoint, &glyph, userdata))
-                    return;
+                kerning = mgl_font_get_kerning(self->font, prev_codepoint, codepoint);
+                glyph_width = glyph.advance * TAB_WIDTH;
+            } else {
+                goto next;
             }
         } else if(codepoint == '\n') {
-            if(!callback(codepoint_index, codepoint, &glyph, userdata))
-                return;
+            kerning = 0.0f;
+            glyph_width = 0.0f;
         } else {
             if(mgl_font_get_glyph(self->font, codepoint, &glyph) == 0) {
-                if(!callback(codepoint_index, codepoint, &glyph, userdata))
-                    return;
+                kerning = mgl_font_get_kerning(self->font, prev_codepoint, codepoint);
+                glyph_width = glyph.advance;
+            } else {
+                goto next;
             }
         }
 
+        if(((glyph_offset.x + kerning + glyph_width > self->max_width) && self->max_width > 0.001f) || codepoint == '\n') {
+            glyph_offset.x = 0.0f;
+            if(codepoint != '\n')
+                glyph_offset.y += self->font->character_size;
+            prev_codepoint = 0;
+
+            ++rows;
+            if(rows == self->max_rows)
+                return;
+        } else {
+            glyph_offset.x += kerning;
+        }
+
+        if(!callback((codepoint_loop_callback_data){ codepoint_index, codepoint, kerning, glyph_width, &glyph, glyph_offset }, userdata))
+            return;
+
+        glyph_offset.x += glyph_width;
+        if(codepoint == '\n')
+            glyph_offset.y += self->font->character_size;
+
+        prev_codepoint = codepoint;
+
+        next:
         i += clen;
         ++codepoint_index;
     }
 }
 
-static float max_float(float a, float b) {
-    return a >= b ? a : b;
-}
-
 typedef struct {
     mgl_vec2f bounds;
-    float line_width;
-    const mgl_font *font;
-    uint32_t prev_codepoint;
 } CalculateBoundsUserdata;
 
-static bool calculate_bounds_callback(size_t codepoint_index, uint32_t codepoint, const mgl_font_glyph *glyph, void *userdata) {
-    (void)codepoint_index;
-
+static bool calculate_bounds_callback(codepoint_loop_callback_data callback_data, void *userdata) {
     CalculateBoundsUserdata *calculate_bounds_userdata = userdata;
-    if(codepoint == '\t') {
-        calculate_bounds_userdata->line_width += (glyph->advance * TAB_WIDTH) + mgl_font_get_kerning(calculate_bounds_userdata->font, calculate_bounds_userdata->prev_codepoint, codepoint);
-        calculate_bounds_userdata->bounds.x = max_float(calculate_bounds_userdata->bounds.x, calculate_bounds_userdata->line_width);
-    } else if(codepoint == '\n') {
-        calculate_bounds_userdata->line_width = 0.0f;
-        calculate_bounds_userdata->bounds.y += calculate_bounds_userdata->font->character_size;
-        calculate_bounds_userdata->prev_codepoint = 0;
-    } else {
-        calculate_bounds_userdata->line_width += glyph->advance + mgl_font_get_kerning(calculate_bounds_userdata->font, calculate_bounds_userdata->prev_codepoint, codepoint);
-        calculate_bounds_userdata->bounds.x = max_float(calculate_bounds_userdata->bounds.x, calculate_bounds_userdata->line_width);
-    }
-
-    calculate_bounds_userdata->prev_codepoint = codepoint;
+    calculate_bounds_userdata->bounds.x = max_float(calculate_bounds_userdata->bounds.x, callback_data.glyph_offset.x + callback_data.glyph_width);
+    calculate_bounds_userdata->bounds.y = max_float(calculate_bounds_userdata->bounds.y, callback_data.glyph_offset.y);
     return true;
 }
 
@@ -78,9 +108,6 @@ static mgl_vec2f mgl_text_calculate_bounds(mgl_text *self) {
     CalculateBoundsUserdata calculate_bounds_userdata;
     calculate_bounds_userdata.bounds.x = 0.0f;
     calculate_bounds_userdata.bounds.y = self->font->character_size;
-    calculate_bounds_userdata.line_width = 0.0f;
-    calculate_bounds_userdata.font = self->font;
-    calculate_bounds_userdata.prev_codepoint = 0;
     mgl_text_for_each_codepoint(self, calculate_bounds_callback, &calculate_bounds_userdata);
     return calculate_bounds_userdata.bounds;
 }
@@ -92,6 +119,8 @@ void mgl_text_init(mgl_text *self, mgl_font *font, const char *str, size_t str_s
     self->text = NULL;
     self->text_size = 0;
     self->bounds_dirty = true;
+    self->max_width = 0.0f;
+    self->max_rows = 0;
     mgl_text_set_string(self, str, str_size);
 }
 
@@ -122,6 +151,18 @@ void mgl_text_set_color(mgl_text *self, mgl_color color) {
     self->color = color;
 }
 
+void mgl_text_set_max_width(mgl_text *self, float max_width) {
+    if(float_abs(max_width - self->max_width < 0.001))
+        self->bounds_dirty = true;
+    self->max_width = max_width;
+}
+
+void mgl_text_set_max_rows(mgl_text *self, unsigned int max_rows) {
+    if(max_rows != self->max_rows)
+        self->bounds_dirty = true;
+    self->max_rows = max_rows;
+}
+
 mgl_vec2f mgl_text_get_bounds(mgl_text *self) {
     if(self->bounds_dirty) {
         self->bounds_dirty = false;
@@ -139,26 +180,13 @@ typedef struct {
     mgl_vec2f position;
     const mgl_text *text;
     size_t index;
-    uint32_t prev_codepoint;
 } FindCharacterPosUserdata;
 
-static bool find_character_pos_callback(size_t codepoint_index, uint32_t codepoint, const mgl_font_glyph *glyph, void *userdata) {
+static bool find_character_pos_callback(codepoint_loop_callback_data callback_data, void *userdata) {
     FindCharacterPosUserdata *find_character_pos_userdata = userdata;
-    if(codepoint_index >= find_character_pos_userdata->index)
-        return false;
-
-    if(codepoint == '\t') {
-        find_character_pos_userdata->position.x += (glyph->advance * TAB_WIDTH) + mgl_font_get_kerning(find_character_pos_userdata->text->font, find_character_pos_userdata->prev_codepoint, codepoint);
-    } else if(codepoint == '\n') {
-        find_character_pos_userdata->position.x = find_character_pos_userdata->text->position.x;
-        find_character_pos_userdata->position.y += find_character_pos_userdata->text->font->character_size;
-        find_character_pos_userdata->prev_codepoint = 0;
-    } else {
-        find_character_pos_userdata->position.x += glyph->advance + mgl_font_get_kerning(find_character_pos_userdata->text->font, find_character_pos_userdata->prev_codepoint, codepoint);
-    }
-
-    find_character_pos_userdata->prev_codepoint = codepoint;
-    return true;
+    find_character_pos_userdata->position.x = find_character_pos_userdata->position.x + callback_data.glyph_offset.x;
+    find_character_pos_userdata->position.y = find_character_pos_userdata->position.y + callback_data.glyph_offset.y;
+    return callback_data.codepoint_index < find_character_pos_userdata->index;
 }
 
 mgl_vec2f mgl_text_find_character_pos(mgl_text *self, size_t index) {
@@ -166,7 +194,6 @@ mgl_vec2f mgl_text_find_character_pos(mgl_text *self, size_t index) {
     find_character_pos_userdata.position = self->position;
     find_character_pos_userdata.text = self;
     find_character_pos_userdata.index = index;
-    find_character_pos_userdata.prev_codepoint = 0;
     mgl_text_for_each_codepoint(self, find_character_pos_callback, &find_character_pos_userdata);
     return (mgl_vec2f){ find_character_pos_userdata.position.x, find_character_pos_userdata.position.y };
 }
@@ -189,24 +216,14 @@ typedef struct {
     mgl_vec2f position;
     const mgl_text *text;
     mgl_context *context;
-    uint32_t prev_codepoint;
 } TextDrawUserdata;
 
-static bool text_draw_callback(size_t codepoint_index, uint32_t codepoint, const mgl_font_glyph *glyph, void *userdata) {
-    (void)codepoint_index;
+static bool text_draw_callback(codepoint_loop_callback_data callback_data, void *userdata) {
     TextDrawUserdata *text_draw_userdata = userdata;
-    if(codepoint == '\t') {
-        text_draw_userdata->position.x += (glyph->advance * TAB_WIDTH) + mgl_font_get_kerning(text_draw_userdata->text->font, text_draw_userdata->prev_codepoint, codepoint);
-    } else if(codepoint == '\n') {
-        text_draw_userdata->position.x = text_draw_userdata->text->position.x;
-        text_draw_userdata->position.y += text_draw_userdata->text->font->character_size;
-        text_draw_userdata->prev_codepoint = 0;
-    } else {
-        text_draw_userdata->position.x += mgl_font_get_kerning(text_draw_userdata->text->font, text_draw_userdata->prev_codepoint, codepoint);
-        mgl_text_draw_glyph(text_draw_userdata->context, glyph, (mgl_vec2i){ text_draw_userdata->position.x, text_draw_userdata->position.y });
-        text_draw_userdata->position.x += glyph->advance;
+    if(callback_data.codepoint != '\t' && callback_data.codepoint != '\n') {
+        mgl_text_draw_glyph(text_draw_userdata->context, callback_data.glyph,
+            (mgl_vec2i){ text_draw_userdata->position.x + callback_data.glyph_offset.x, text_draw_userdata->position.y + callback_data.glyph_offset.y });
     }
-    text_draw_userdata->prev_codepoint = codepoint;
     return true;
 }
 
@@ -224,7 +241,6 @@ void mgl_text_draw(mgl_context *context, mgl_text *text) {
     text_draw_userdata.position = (mgl_vec2f){ text->position.x, text->position.y };
     text_draw_userdata.text = text;
     text_draw_userdata.context = context;
-    text_draw_userdata.prev_codepoint = 0;
 
     mgl_window_set_texture_blend_func(context->current_window);
 
diff --git a/tests/main.c b/tests/main.c
index f52e3d4..3ec5738 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -61,6 +61,8 @@ static void draw(mgl_window *window, void *userdata) {
 
     mgl_text text;
     mgl_text_init(&text, u->font, str, strlen(str));
+    mgl_text_set_max_width(&text, 200.0f);
+    mgl_text_set_max_rows(&text, 5);
     mgl_text_draw(context, &text);
     mgl_text_deinit(&text);