scroll_engine: Major rework to support pixel-based scrolling and scroll callbacks.

Much of the scrolling work is moved from lcd-bitmap-common to lcd-scroll.c,
a small scroll callback routine remains. This callback can potentially be
overridden by more extensive scrollers.

The callback also gets fed with pixel-based scrolling information, which
finally removes the strict line-based nature of the scroll engine. Along with
this is the change from scroll_stop_viewport_line() to scroll_stop_viewport_rect()
which works on a pixel-based rectangle instead of lines.

The ultimate goal is to move most of the scroll work to apps, which can
much better decide which line decorations to apply etc. This work is laying
the ground work.

Change-Id: I3b2885cf7d8696ddd9253d5a9a73318d3d42831a

1 files changed, 64 insertions, 116 deletions

diff --git a/firmware/drivers/lcd-bitmap-common.c b/firmware/drivers/lcd-bitmap-common.c
index c04f57ef22..f3e700a4a1 100644
--- a/firmware/drivers/lcd-bitmap-common.c
+++ b/firmware/drivers/lcd-bitmap-common.c
@@ -412,12 +412,10 @@ static void LCDFN(putsxyofs_style)(int xpos, int ypos,
 
 /*** Line oriented text output ***/
 
-/* put a string at a given char position */
 void LCDFN(puts_style_xyoffset)(int x, int y, const unsigned char *str,
                               int style, int x_offset, int y_offset)
 {
     int xpos, ypos, h;
-    LCDFN(scroll_stop_viewport_line)(current_vp, y);
     if(!str)
         return;
 
@@ -425,14 +423,15 @@ void LCDFN(puts_style_xyoffset)(int x, int y, const unsigned char *str,
     if ((style&STYLE_XY_PIXELS) == 0)
     {
         xpos = x * LCDFN(getstringsize)(" ", NULL, NULL);
-        ypos = y * h + y_offset;
+        ypos = y * h;
     }
     else
     {
         xpos = x;
-        ypos = y + y_offset;
+        ypos = y;
     }
-    LCDFN(putsxyofs_style)(xpos, ypos, str, style, h, x_offset);
+    LCDFN(scroll_stop_viewport_rect)(current_vp, x, y, current_vp->width - x, h);
+    LCDFN(putsxyofs_style)(xpos, ypos+y_offset, str, style, h, x_offset);
 }
 
 void LCDFN(puts_style_offset)(int x, int y, const unsigned char *str,
@@ -469,7 +468,7 @@ void LCDFN(puts_offset)(int x, int y, const unsigned char *str, int offset)
 
 /*** scrolling ***/
 
-static struct scrollinfo* find_scrolling_line(int line)
+static struct scrollinfo* find_scrolling_line(int x, int y)
 {
     struct scrollinfo* s = NULL;
     int i;
@@ -477,93 +476,101 @@ static struct scrollinfo* find_scrolling_line(int line)
     for(i=0; i<LCDFN(scroll_info).lines; i++)
     {
         s = &LCDFN(scroll_info).scroll[i];
-        if (s->y == line && s->vp == current_vp)
+        if (s->x == x && s->y == y && s->vp == current_vp)
             return s;
     }
     return NULL;
 }
 
-void LCDFN(puts_scroll_style_xyoffset)(int x, int y, const unsigned char *string,
-                                     int style, int x_offset, int y_offset)
+void LCDFN(scroll_fn)(struct scrollinfo* s)
+{
+    LCDFN(putsxyofs_style)(s->x, s->y, s->line, s->style, s->height, s->offset);
+}
+
+static void LCDFN(puts_scroll_worker)(int x, int y, const unsigned char *string,
+                                     int style, int x_offset, int y_offset,
+                                     bool linebased,
+                                     void (*scroll_func)(struct scrollinfo *),
+                                     void *data)
 {
     struct scrollinfo* s;
-    char *end;
-    int w, h;
-    int len;
-    bool restart = false;
-    int space_width;
+    int width, height;
+    int w, h, cwidth, margin;
+    bool restart;
 
-    if (!string || ((unsigned)y >= (unsigned)current_vp->height))
+    if (!string)
         return;
 
-    s = find_scrolling_line(y);
-    if (!s)
-        restart = true;
+    /* prepare rectangle for scrolling. x and y must be calculated early
+     * for find_scrolling_line() to work */
+    cwidth = font_get(current_vp->font)->maxwidth;
+    height = current_vp->line_height ?: (int)font_get(current_vp->font)->height;
+    y = y * (linebased ? height : 1) + y_offset;
+    x = x * (linebased ? cwidth : 1);
+    width = current_vp->width - x;
 
-    if (restart)
-    {
+    if (y >= current_vp->height)
+        return;
+
+    s = find_scrolling_line(x, y);
+    restart = !s;
+
+    if (restart) {
         /* remove any previously scrolling line at the same location */
-        LCDFN(scroll_stop_viewport_line)(current_vp, y);
+        LCDFN(scroll_stop_viewport_rect)(current_vp, x, y, width, height);
+        LCDFN(putsxyofs_style)(x, y, string, style, height, x_offset);
 
-        if (LCDFN(scroll_info).lines >= LCDM(SCROLLABLE_LINES)) return;
-        LCDFN(puts_style_xyoffset)(x, y, string, style, x_offset, y_offset);
+        if (LCDFN(scroll_info).lines >= LCDM(SCROLLABLE_LINES))
+            return;
     }
 
+    /* get width (pixeks) of the string */
     LCDFN(getstringsize)(string, &w, &h);
 
-    if (current_vp->width - x * 8 >= w)
+    /* check if scrolling is actually necessary (consider the actual start
+     * of the line) */
+    margin = x * linebased ? cwidth : 1;
+    if (current_vp->width >= margin+w)
         return;
 
-    if (restart)
-    {
+    if (restart) {
         /* prepare scroll line */
         s = &LCDFN(scroll_info).scroll[LCDFN(scroll_info).lines];
         s->start_tick = current_tick + LCDFN(scroll_info).delay;
     }
-    strlcpy(s->line, string, sizeof s->line);
-    space_width = LCDFN(getstringsize)(" ", NULL, NULL);
 
-    /* get width */
-    LCDFN(getstringsize)(s->line, &w, &h);
-    if (!restart && s->width > w)
-    {
-        if (s->startx > w)
-            s->startx = w;
-    }
-    s->width = w;
-
-    /* scroll bidirectional or forward only depending on the string
-       width */
+    /* copy contents to the line buffer */
+    strlcpy(s->linebuffer, string, sizeof(s->linebuffer));
+    /* scroll bidirectional or forward only depending on the string width */
     if ( LCDFN(scroll_info).bidir_limit ) {
-        s->bidir = s->width < (current_vp->width) *
+        s->bidir = w < (current_vp->width) *
             (100 + LCDFN(scroll_info).bidir_limit) / 100;
     }
     else
         s->bidir = false;
 
-    if (!s->bidir) { /* add spaces if scrolling in the round */
-        strlcat(s->line, "   ", sizeof s->line);
-        /* get new width incl. spaces */
-        s->width += space_width * 3;
-    }
-
-    end = strchr(s->line, '\0');
-    len = sizeof s->line - (end - s->line);
-    strlcpy(end, string, MIN(current_vp->width/2, len));
+    s->scroll_func = scroll_func;
+    s->userdata = data;
 
-    s->vp = current_vp;
-    s->y = y;
-    if (restart)
-    {
+    if (restart) {
         s->offset = x_offset;
-        s->startx = x * space_width;
         s->backward = false;
         s->style = style;
+        /* assign the rectangle. not necessary if continuing an earlier line */
+        s->x = x;
+        s->y = y;
+        s->width = width;
+        s->height = height;
+        s->vp = current_vp;
+        LCDFN(scroll_info).lines++;
     }
-    s->y_offset = y_offset;
+}
 
-    if (restart)
-        LCDFN(scroll_info).lines++;
+void LCDFN(puts_scroll_style_xyoffset)(int x, int y, const unsigned char *string,
+                                     int style, int x_offset, int y_offset)
+{
+    LCDFN(puts_scroll_worker)(x, y, string, style, x_offset, y_offset,
+                              true, LCDFN(scroll_fn), NULL);
 }
 
 void LCDFN(puts_scroll)(int x, int y, const unsigned char *string)
@@ -583,65 +590,6 @@ void LCDFN(puts_scroll_offset)(int x, int y, const unsigned char *string,
      LCDFN(puts_scroll_style_offset)(x, y, string, STYLE_DEFAULT, offset);
 }
 
-void LCDFN(scroll_fn)(void)
-{
-    struct scrollinfo* s;
-    int index;
-    int xpos, ypos, height;
-    struct viewport* old_vp = current_vp;
-    bool makedelay;
-
-    for ( index = 0; index < LCDFN(scroll_info).lines; index++ ) {
-        s = &LCDFN(scroll_info).scroll[index];
-
-        /* check pause */
-        if (TIME_BEFORE(current_tick, s->start_tick))
-            continue;
-
-        LCDFN(set_viewport)(s->vp);
-        height = s->vp->line_height ?: (int)font_get(s->vp->font)->height;
-
-        if (s->backward)
-            s->offset -= LCDFN(scroll_info).step;
-        else
-            s->offset += LCDFN(scroll_info).step;
-
-        xpos = s->startx;
-        ypos = s->y * height + s->y_offset;
-
-        makedelay = false;
-        if (s->bidir) { /* scroll bidirectional */
-            if (s->offset <= 0) {
-                /* at beginning of line */
-                s->offset = 0;
-                s->backward = false;
-                makedelay = true;
-            }
-            else if (s->offset >= s->width - (current_vp->width - xpos)) {
-                /* at end of line */
-                s->offset = s->width - (current_vp->width - xpos);
-                s->backward = true;
-                makedelay = true;
-            }
-        }
-        else {
-            /* scroll forward the whole time */
-            if (s->offset >= s->width) {
-                s->offset = 0;
-                makedelay = true;
-            }
-        }
-
-        if (makedelay)
-            s->start_tick = current_tick + LCDFN(scroll_info).delay +
-                    LCDFN(scroll_info).ticks;
-
-        LCDFN(putsxyofs_style)(xpos, ypos, s->line, s->style, height, s->offset);
-        LCDFN(update_viewport_rect)(xpos, ypos, current_vp->width-xpos, height);
-    }
-    LCDFN(set_viewport)(old_vp);
-}
-
 void LCDFN(puts_scroll_style_offset)(int x, int y, const unsigned char *string,
                                      int style, int x_offset)
 {