scrolling working

1 files changed, 82 insertions, 33 deletions

diff --git a/buffer.c b/buffer.c
index f98e3f3..f06ca00 100644
--- a/buffer.c
+++ b/buffer.c
@@ -21,16 +21,17 @@ typedef struct {
 } TextBlock;
 
 typedef struct {
-	u32 nblocks; // number of text blocks
 	double scroll_x, scroll_y; // number of characters scrolled in the x/y direction
-	TextBlock *blocks;
 	Font *font;
+	u8 tab_width;
 	float x1, y1, x2, y2;
+	u32 nblocks; // number of text blocks
+	TextBlock *blocks;
 } TextBuffer;
 
 // Returns a new block added at index `where`,
 // or NULL if there's not enough memory.
-static TextBlock *text_buffer_add_block(TextBuffer *buffer, u32 where) {
+static TextBlock *buffer_add_block(TextBuffer *buffer, u32 where) {
 	// make sure we can actually allocate enough memory for the contents of the block
 	// before doing anything
 	char *block_contents = calloc(1, TEXT_BLOCK_MAX_SIZE);
@@ -63,12 +64,13 @@ static TextBlock *text_buffer_add_block(TextBuffer *buffer, u32 where) {
 	return block;
 }
 
-void text_buffer_create(TextBuffer *buffer, Font *font) {
+void buffer_create(TextBuffer *buffer, Font *font) {
 	util_zero_memory(buffer, sizeof *buffer);
 	buffer->font = font;
+	buffer->tab_width = 4;
 }
 
-Status text_buffer_load_file(TextBuffer *buffer, FILE *fp) {
+Status buffer_load_file(TextBuffer *buffer, FILE *fp) {
 	char block_contents[TEXT_BLOCK_DEFAULT_SIZE];
 	size_t bytes_read;
 	// @TODO: @TODO: IMPORTANT! make this work if buffer already has a file
@@ -77,7 +79,7 @@ Status text_buffer_load_file(TextBuffer *buffer, FILE *fp) {
 	do {
 		bytes_read = fread(block_contents, 1, sizeof block_contents, fp);
 		if (bytes_read > 0) {
-			TextBlock *block = text_buffer_add_block(buffer, buffer->nblocks);
+			TextBlock *block = buffer_add_block(buffer, buffer->nblocks);
 			if (!block) {
 				return false;
 			}
@@ -90,8 +92,8 @@ Status text_buffer_load_file(TextBuffer *buffer, FILE *fp) {
 	return true;
 }
 
-static void text_buffer_print_internal(TextBuffer *buffer, bool debug) {
-	printf("\033[2J\033[;H");
+static void buffer_print_internal(TextBuffer *buffer, bool debug) {
+	printf("\033[2J\033[;H"); // clear terminal screen
 	TextBlock *blocks = buffer->blocks;
 	u32 nblocks = buffer->nblocks;
 	
@@ -105,17 +107,17 @@ static void text_buffer_print_internal(TextBuffer *buffer, bool debug) {
 }
 
 // print the contents of a buffer to stdout
-void text_buffer_print(TextBuffer *buffer) {
-	text_buffer_print_internal(buffer, false);
+void buffer_print(TextBuffer *buffer) {
+	buffer_print_internal(buffer, false);
 }
 
 // print the contents of a buffer to stdout, along with debugging information
-void text_buffer_print_debug(TextBuffer *buffer) {
-	text_buffer_print_internal(buffer, true);
+void buffer_print_debug(TextBuffer *buffer) {
+	buffer_print_internal(buffer, true);
 }
 
 // Does not free the pointer `buffer` (buffer might not have even been allocated with malloc)
-void text_buffer_free(TextBuffer *buffer) {
+void buffer_free(TextBuffer *buffer) {
 	TextBlock *blocks = buffer->blocks;
 	u32 nblocks = buffer->nblocks;
 	for (u32 i = 0; i < nblocks; ++i) {
@@ -124,30 +126,87 @@ void text_buffer_free(TextBuffer *buffer) {
 	free(blocks);
 }
 
+// returns the number of lines of text in the buffer into *lines (if not NULL),
+// and the number of columns of text, i.e. the length of the longest line, into *cols (if not NULL)
+static void buffer_text_dimensions(TextBuffer *buffer, u64 *lines, u64 *cols) {
+	u64 nlines = 1;
+	u64 maxcol = 0;
+	u64 col = 0;
+	for (u32 i = 0; i < buffer->nblocks; ++i) {
+		TextBlock *block = &buffer->blocks[i];
+		for (char *p = block->contents, *end = p + block->len; p != end; ++p) {
+			switch (*p) {
+			case '\n':
+				++nlines;
+				col = 0;
+				break;
+			case '\r': break;
+			case '\t':
+				do
+					++col;
+				while (col % buffer->tab_width);
+				break;
+			default:
+				++col;
+				break;
+			}
+			if (col > maxcol)
+				maxcol = col;
+		}
+	}
+	if (lines) *lines = nlines;
+	if (cols) *cols = maxcol;
+}
+
+
+// returns the number of rows of text that can fit in the buffer, rounded down.
+int buffer_display_rows(TextBuffer *buffer) {
+	return (int)((buffer->y2 - buffer->y1) / text_font_char_height(buffer->font));
+}
+
+// returns the number of columns of text that can fit in the buffer, rounded down.
+int buffer_display_cols(TextBuffer *buffer) {
+	return (int)((buffer->x2 - buffer->x1) / text_font_char_width(buffer->font));
+}
 // make sure we don't scroll too far
-static void text_buffer_correct_scroll(TextBuffer *buffer) {
+static void buffer_correct_scroll(TextBuffer *buffer) {
 	if (buffer->scroll_x < 0)
 		buffer->scroll_x = 0;
 	if (buffer->scroll_y < 0)
 		buffer->scroll_y = 0;
-	// @TODO: maximum scroll_x and scroll_y
+	u64 nlines, ncols;
+	buffer_text_dimensions(buffer, &nlines, &ncols);
+	double max_scroll_x = (double)ncols  - buffer_display_cols(buffer);
+	double max_scroll_y = (double)nlines - buffer_display_rows(buffer);
+	if (max_scroll_x <= 0) {
+		buffer->scroll_x = 0;
+	} else if (buffer->scroll_x > max_scroll_x) {
+		buffer->scroll_x = max_scroll_x;
+	}
+
+	if (max_scroll_y <= 0) {
+		buffer->scroll_y = 0;
+	} else if (buffer->scroll_y > max_scroll_y) {
+		buffer->scroll_y = max_scroll_y;
+	}
 }
 
-void text_buffer_scroll(TextBuffer *buffer, double dx, double dy) {
+void buffer_scroll(TextBuffer *buffer, double dx, double dy) {
 	buffer->scroll_x += dx;
 	buffer->scroll_y += dy;
-	text_buffer_correct_scroll(buffer);
+	buffer_correct_scroll(buffer);
 }
 
 // Render the text buffer in the given rectangle
 // NOTE: also corrects scroll
-void text_buffer_render(TextBuffer *buffer, float x1, float y1, float x2, float y2) {
+void buffer_render(TextBuffer *buffer, float x1, float y1, float x2, float y2) {
 	buffer->x1 = x1; buffer->y1 = y1; buffer->x2 = x2; buffer->y2 = y2;
 	Font *font = buffer->font;
 	mbstate_t mbstate = {0};
-	uint nblocks = buffer->nblocks;
+	u32 nblocks = buffer->nblocks;
 	TextBlock *blocks = buffer->blocks;
-	float char_height = text_font_char_height(font);
+	float char_width = text_font_char_width(font),
+		char_height = text_font_char_height(font);
 	glColor3f(0.5f,0.5f,0.5f);
 	glBegin(GL_LINE_STRIP);
 	glVertex2f(x1,y1);
@@ -161,7 +220,7 @@ void text_buffer_render(TextBuffer *buffer, float x1, float y1, float x2, float
 	text_chars_begin(font);
 
 	// what x coordinate to start rendering the text from
-	float render_start_x = x1 - (float)buffer->scroll_x * char_height;
+	float render_start_x = x1 - (float)buffer->scroll_x * char_width;
 
 	u32 column = 0;
 
@@ -174,7 +233,7 @@ void text_buffer_render(TextBuffer *buffer, float x1, float y1, float x2, float
 	// @TODO: make this better (we should figure out where to start rendering, etc.)
 	text_state.y -= (float)buffer->scroll_y * char_height;
 
-	for (uint block_idx = 0; block_idx < nblocks; ++block_idx) {
+	for (u32 block_idx = 0; block_idx < nblocks; ++block_idx) {
 		TextBlock *block = &blocks[block_idx];
 		char *p = block->contents, *end = p + block->len;
 		while (p != end) {
@@ -208,7 +267,7 @@ void text_buffer_render(TextBuffer *buffer, float x1, float y1, float x2, float
 				do {
 					text_render_char(font, L' ', &text_state);
 					++column;
-				} while (column % 4);
+				} while (column % buffer->tab_width);
 				break;
 			default:
 				text_render_char(font, c, &text_state);
@@ -219,13 +278,3 @@ void text_buffer_render(TextBuffer *buffer, float x1, float y1, float x2, float
 	}
 	text_chars_end(font);
 }
-
-// returns the number of rows of text that can fit in the buffer, rounded down.
-int text_buffer_num_rows(TextBuffer *buffer) {
-	return (int)((buffer->y2 - buffer->y1) / text_font_char_height(buffer->font));
-}
-
-// returns the number of columns of text that can fit in the buffer, rounded down.
-int text_buffer_num_cols(TextBuffer *buffer) {
-	return (int)((buffer->x2 - buffer->x1) / text_font_char_width(buffer->font));
-}