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-rw-r--r--source/nds/draw.c277
1 files changed, 89 insertions, 188 deletions
diff --git a/source/nds/draw.c b/source/nds/draw.c
index a0006ac..aa56f20 100644
--- a/source/nds/draw.c
+++ b/source/nds/draw.c
@@ -402,12 +402,29 @@ struct scroll_string_info{
static struct scroll_string_info scroll_strinfo[MAX_SCROLL_STRING];
static u32 scroll_string_num= 0;
+/*
+ * Initialises a text scroller to display a certain string.
+ * Input assertions: sx + width < NDS_SCREEN_WIDTH &&
+ * sy + [text height] < NDS_SCREEN_HEIGHT && string != NULL &&
+ * screen_addr != NULL.
+ * Input: 'screen_addr', the address of the upper-left corner of the screen.
+ * 'sx' and 'sy', the X and Y coordinates of the upper-left corner of
+ * the text.
+ * 'width', the width of the scroller's viewport.
+ * 'color_bg', the RGB15 color of the background around the text, or
+ * COLOR_TRANS for transparency.
+ * 'color_fg', the RGB15 color of the text.
+ * 'string', the text to be scrolled, encoded as UTF-8.
+ * Output: the scroller's handle, to be used to scroll the text in
+ * draw_hscroll.
+ */
u32 draw_hscroll_init(void* screen_addr, u32 sx, u32 sy, u32 width,
u32 color_bg, u32 color_fg, char *string)
{
- u32 index, x, num, len, i;
+ u32 index, x, textWidth, num, len, i;
u16 *unicode, *screenp;
+ // 1. Which scroller should we use for this request?
for(i= 0; i < MAX_SCROLL_STRING; i++)
{
if(scroll_strinfo[i].screenp == NULL)
@@ -418,23 +435,39 @@ u32 draw_hscroll_init(void* screen_addr, u32 sx, u32 sy, u32 width,
return -1;
index= i;
- screenp= (u16*)malloc((256+128)*FONTS_HEIGHT*2);
- if(screenp == NULL)
+
+ // 2. Convert to Unicode while calculating the width of the text.
+ unicode= (u16*)malloc(strlen(string)*sizeof(u16));
+ if(unicode == NULL)
{
scroll_strinfo[index].str_len = 0;
- return -2;
+ return -3;
}
- unicode= (u16*)malloc(256*2);
- if(unicode == NULL)
+ num= 0;
+ textWidth = 0;
+ while(*string)
+ {
+ string= utf8decode(string, unicode+num);
+ if(unicode[num] != 0x0D && unicode[num] != 0x0A) {
+ textWidth += BDF_width16_ucs(unicode[num]);
+ num++;
+ }
+ }
+ if (textWidth < width)
+ textWidth = width;
+
+ // 3. Allocate a rectangle of pixels for drawing the entire text into.
+ screenp= (u16*)malloc(textWidth*FONTS_HEIGHT*sizeof(u16));
+ if(screenp == NULL)
{
scroll_strinfo[index].str_len = 0;
- free((void*)screenp);
- return -3;
+ free((void*)unicode);
+ return -2;
}
if(color_bg == COLOR_TRANS)
- memset(screenp, 0, (256+128)*FONTS_HEIGHT*2);
+ memset(screenp, 0, textWidth*FONTS_HEIGHT*sizeof(u16));
scroll_string_num += 1;
scroll_strinfo[index].screenp = (unsigned short*)screen_addr;
@@ -447,208 +480,74 @@ u32 draw_hscroll_init(void* screen_addr, u32 sx, u32 sy, u32 width,
scroll_strinfo[index].unicode= unicode;
scroll_strinfo[index].buff_fonts= screenp;
scroll_strinfo[index].buff_bg= 0;
-
- num= 0;
- while(*string)
- {
- string= utf8decode(string, unicode+num);
- if(unicode[num] != 0x0D && unicode[num] != 0x0A) num++;
- }
+ scroll_strinfo[index].buff_width= textWidth;
+ scroll_strinfo[index].pos_pixel= 0;
+ scroll_strinfo[index].str_start= 0;
+ scroll_strinfo[index].str_end= len-1;
scroll_strinfo[index].str_len= num;
if(num == 0)
- return index;
+ return index; // (1. Which scroller?)
- len= BDF_cut_unicode(unicode, num, 256+128, 1);
+ // 4. Render text into the allocation.
i= 0;
x= 0;
- while(i < len)
- {
- x += BDF_render16_ucs(screenp + x, 256+128, 0, color_bg, color_fg, unicode[i++]);
- }
-
- scroll_strinfo[index].buff_width= x;
- scroll_strinfo[index].pos_pixel= 0;
- scroll_strinfo[index].str_start= 0;
- scroll_strinfo[index].str_end= len-1;
-
- num= scroll_strinfo[index].height;
- len= width;
-
- u16 *screenp1;
-
- if(color_bg == COLOR_TRANS)
+ while(i < num)
{
- u16 pixel;
-
- for(i= 0; i < num; i++)
- {
- screenp= (unsigned short*)screen_addr + sx + (sy + i) * SCREEN_WIDTH;
- screenp1= scroll_strinfo[index].buff_fonts + i*(256+128);
- for(x= 0; x < len; x++)
- {
- pixel= *screenp1++;
- if(pixel) *screenp = pixel;
- screenp ++;
- }
- }
+ x += BDF_render16_ucs(screenp + x, textWidth, 0, color_bg, color_fg, unicode[i++]);
}
- else
- {
- screenp= (unsigned short*)screen_addr + sx + sy * SCREEN_WIDTH;
- screenp1= scroll_strinfo[index].buff_fonts;
- for(i= 0; i < num; i++)
- {
- memcpy((char*)screenp, (char*)screenp1, len*2);
- screenp += SCREEN_WIDTH;
- screenp1 += (256+128);
- }
- }
+ // 5. Draw text to the screen at its initial position (left justified).
+ draw_hscroll(index, 0 /* stay on the left */);
- return index;
+ return index; // (1. Which scroller?)
}
+/*
+ * Scrolls an initialised scroller's text.
+ * A scroller is never allowed to go past the beginning of the text when
+ * scrolling to the left, or to go past the end when scrolling to the right.
+ * Input assertions: index was returned by a previous call to
+ * draw_hscroll_init and not used in a call to draw_hscroll_over.
+ * Input: 'index', the scroller's handle.
+ * 'scroll_val', the number of pixels to scroll. The sign affects the
+ * direction. If scroll_val > 0, the scroller's viewport is moved to
+ * the left; if < 0, the scroller's viewport is moved to the right.
+ * Output: the number of pixels still available to scroll in the direction
+ * specified by the sign of 'scroll_val'.
+ *
+ * Example: (assume each letter is 1 pixel; this won't be true in reality)
+ * [some lengthy text shown in ] |
+ * val -5 -> | [lengthy text shown in a scr]xxxxx -> to right, returns 5
+ * val -5 -> | [hy text shown in a scroller] -> to right, returns 0
+ * val 3 -> xxxxxxx[ngthy text shown in a scrol] | -> to left, returns 7
+ * val 3 -> xxxx[ lengthy text shown in a sc] | -> to left, returns 4
+ */
u32 draw_hscroll(u32 index, s32 scroll_val)
{
u32 color_bg, color_fg, i, width, height;
s32 xoff;
-//static int flag= 0;
-
if(index >= MAX_SCROLL_STRING) return -1;
if(scroll_strinfo[index].screenp == NULL) return -2;
if(scroll_strinfo[index].str_len == 0) return 0;
width= scroll_strinfo[index].width;
height= scroll_strinfo[index].height;
- xoff= scroll_strinfo[index].pos_pixel - scroll_val;
color_bg= scroll_strinfo[index].color_bg;
color_fg= scroll_strinfo[index].color_fg;
- if(scroll_val > 0) //shift right
- {
- if(xoff <= 0)
- {
- if(scroll_strinfo[index].str_start > 0)
- {
- u32 x, y, len;
- u16 *unicode;
- u32 *ptr;
- //we assume the malloced memory are 4 bytes aligned, or else this method is wrong
- y= height*width;
- ptr= (u32*)scroll_strinfo[index].buff_fonts;
- y= ((256+128)*FONTS_HEIGHT*2+3)/4;
- x= 0;
- while(x<y) ptr[x++] = 0;
-
- unicode= scroll_strinfo[index].unicode + scroll_strinfo[index].str_end;
- len= scroll_strinfo[index].str_end +1;
- x= (scroll_val > SCREEN_WIDTH/4) ? scroll_val : SCREEN_WIDTH/4;
- y= BDF_cut_unicode(unicode, len, x, 0);
- if(y < len) y += 1;
-
- if(y < scroll_strinfo[index].str_start)
- scroll_strinfo[index].str_start -= y;
- else
- {
- y= scroll_strinfo[index].str_start;
- scroll_strinfo[index].str_start = 0;
- }
-
- len= scroll_strinfo[index].str_len - scroll_strinfo[index].str_start;
- unicode= scroll_strinfo[index].unicode + scroll_strinfo[index].str_start;
- x= 0;
- i= 0;
- while(i < y)
- {
- x += BDF_render16_ucs(scroll_strinfo[index].buff_fonts + x, 256+128, 0,
- color_bg, color_fg, unicode[i++]);
- if(x >= (256+128-14)) break;
- }
-
- y= x;
- while(i < len)
- {
- x += BDF_render16_ucs(scroll_strinfo[index].buff_fonts + x, 256+128, 0,
- color_bg, color_fg, unicode[i++]);
- if(x >= (256+128-14)) break;
- }
-
- scroll_strinfo[index].pos_pixel += y - scroll_val;
- if((scroll_strinfo[index].pos_pixel + width) > (256+128))
- scroll_strinfo[index].pos_pixel= 0;
- scroll_strinfo[index].buff_width= x;
- scroll_strinfo[index].str_end = scroll_strinfo[index].str_start + i -1;
- }
- else
- {
- if(scroll_strinfo[index].pos_pixel > 0)
- scroll_strinfo[index].pos_pixel= 0;
- else
- return 0;
- }
-
- xoff= scroll_strinfo[index].pos_pixel;
- }
- else
- scroll_strinfo[index].pos_pixel= xoff;
- }
- else if(xoff < (s32)scroll_strinfo[index].buff_width) //shift left
- {
- if((scroll_strinfo[index].buff_width + width) > (256+128))
- if((xoff + width) > scroll_strinfo[index].buff_width)
- {
- u32 x, y, len;
- u16 *unicode;
- u32 *ptr;
- //we assume the malloced memory are 4 bytes aligned, or else this method is wrong
- y= height*width;
- ptr= (u32*)scroll_strinfo[index].buff_fonts;
- y= ((256+128)*FONTS_HEIGHT*2+3)/4;
- x= 0;
- while(x<y) ptr[x++] = 0;
-
- unicode= scroll_strinfo[index].unicode + scroll_strinfo[index].str_start;
- len= scroll_strinfo[index].str_len - scroll_strinfo[index].str_start;
- x= (scroll_val > SCREEN_WIDTH/4) ? scroll_val : SCREEN_WIDTH/4;
- x= ((s32)x < xoff) ? x : xoff;
- y= BDF_cut_unicode(unicode, len, x, 1);
-
- scroll_strinfo[index].str_start += y;
- len= scroll_strinfo[index].str_len - scroll_strinfo[index].str_start;
- y= scroll_strinfo[index].str_end - scroll_strinfo[index].str_start +1;
- unicode= scroll_strinfo[index].unicode + scroll_strinfo[index].str_start;
- x= 0;
- i= 0;
- while(i < y)
- {
- x += BDF_render16_ucs(scroll_strinfo[index].buff_fonts + x, 256+128, 0,
- color_bg, color_fg, unicode[i++]);
- }
-
- xoff -= scroll_strinfo[index].buff_width - x;
-
- while(i < len)
- {
- x += BDF_render16_ucs(scroll_strinfo[index].buff_fonts + x, 256+128, 0,
- color_bg, color_fg, unicode[i++]);
- if(x >= (256+128-14)) break;
- }
-
- scroll_strinfo[index].buff_width= x;
- scroll_strinfo[index].str_end = scroll_strinfo[index].str_start + i -1;
- }
-
- scroll_strinfo[index].pos_pixel= xoff;
- }
- else
- return 0;
+ // 1. Shift the scroller.
+ scroll_strinfo[index].pos_pixel -= scroll_val;
+ if (scroll_strinfo[index].pos_pixel < 0) // Reached the beginning
+ scroll_strinfo[index].pos_pixel = 0;
+ else if (scroll_strinfo[index].pos_pixel > scroll_strinfo[index].buff_width - width) // Reached the end
+ scroll_strinfo[index].pos_pixel = scroll_strinfo[index].buff_width - width;
+ // 2. Draw the scroller's text at its new position.
u32 x, sx, sy, pixel;
u16 *screenp, *screenp1;
- color_bg = scroll_strinfo[index].color_bg;
sx= scroll_strinfo[index].sx;
sy= scroll_strinfo[index].sy;
@@ -657,7 +556,7 @@ u32 draw_hscroll(u32 index, s32 scroll_val)
for(i= 0; i < height; i++)
{
screenp= scroll_strinfo[index].screenp + sx + (sy + i) * SCREEN_WIDTH;
- screenp1= scroll_strinfo[index].buff_fonts + xoff + i*(256+128);
+ screenp1= scroll_strinfo[index].buff_fonts + scroll_strinfo[index].pos_pixel + i*scroll_strinfo[index].buff_width;
for(x= 0; x < width; x++)
{
pixel= *screenp1++;
@@ -671,19 +570,21 @@ u32 draw_hscroll(u32 index, s32 scroll_val)
for(i= 0; i < height; i++)
{
screenp= scroll_strinfo[index].screenp + sx + (sy + i) * SCREEN_WIDTH;
- screenp1= scroll_strinfo[index].buff_fonts + xoff + i*(256+128);
+ screenp1= scroll_strinfo[index].buff_fonts + scroll_strinfo[index].pos_pixel + i*scroll_strinfo[index].buff_width;
for(x= 0; x < width; x++)
*screenp++ = *screenp1++;
}
}
- u32 ret;
+ // 3. Return how many more pixels we can scroll in the same direction.
if(scroll_val > 0)
- ret= scroll_strinfo[index].pos_pixel;
+ // Scrolling to the left: Return the number of pixels we can still go
+ // to the left.
+ return scroll_strinfo[index].pos_pixel;
else
- ret= scroll_strinfo[index].buff_width - scroll_strinfo[index].pos_pixel;
-
- return ret;
+ // Scrolling to the right: Return the number of pixels we can still go
+ // to the right.
+ return scroll_strinfo[index].buff_width - scroll_strinfo[index].pos_pixel - width;
}
void draw_hscroll_over(u32 index)
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-09 23:39:38 +0000