scrolling working

3 files changed, 101 insertions, 51 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));
-}
diff --git a/main.c b/main.c
index 6831229..de72bbd 100644
--- a/main.c
+++ b/main.c
@@ -35,7 +35,7 @@ INT WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
 int main(void) {
 #endif
 	setlocale(LC_ALL, ""); // allow unicode
-	SDL_SetHint(SDL_HINT_NO_SIGNAL_HANDLERS, "1"); // if this program is sent a SIGTERM/SIGINT, don't turn it into a quit event 
+	SDL_SetHint(SDL_HINT_NO_SIGNAL_HANDLERS, "1"); // if this program is sent a SIGTERM/SIGINT, don't turn it into a quit event
 	if (SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER) < 0)
 		die("%s", SDL_GetError());
 
@@ -66,12 +66,12 @@ int main(void) {
 	
 	bool quit = false;
 	TextBuffer text_buffer;
-	text_buffer_create(&text_buffer, font);
+	buffer_create(&text_buffer, font);
 
 	{
-		FILE *fp = fopen("test.txt", "r");
+		FILE *fp = fopen("main.c", "r");
 		assert(fp);
-		bool success = text_buffer_load_file(&text_buffer, fp);
+		bool success = buffer_load_file(&text_buffer, fp);
 		fclose(fp);
 		if (!success)
 			die("Error loading file.");
@@ -94,15 +94,15 @@ int main(void) {
 				// scroll with mouse wheel
 				Sint32 dx = event.wheel.x, dy = -event.wheel.y;
 				double scroll_speed = 2.5;
-				text_buffer_scroll(&text_buffer, dx * scroll_speed, dy * scroll_speed);
+				buffer_scroll(&text_buffer, dx * scroll_speed, dy * scroll_speed);
 			} break;
 			case SDL_KEYDOWN: {
 				switch (event.key.keysym.sym) {
 				case SDLK_PAGEUP:
-					text_buffer_scroll(&text_buffer, 0, -text_buffer_num_rows(&text_buffer));
+					buffer_scroll(&text_buffer, 0, -buffer_display_rows(&text_buffer));
 					break;
 				case SDLK_PAGEDOWN:
-					text_buffer_scroll(&text_buffer, 0, +text_buffer_num_rows(&text_buffer));
+					buffer_scroll(&text_buffer, 0, +buffer_display_rows(&text_buffer));
 					break;
 				}
 			} break;
@@ -122,15 +122,16 @@ int main(void) {
 		if (control_key_down) {
 			// control + arrow keys to scroll
 			double scroll_speed = 20.0;
-			double scroll_amount = scroll_speed * frame_dt;
+			double scroll_amount_x = scroll_speed * frame_dt * 1.5; // characters are taller than they are wide
+			double scroll_amount_y = scroll_speed * frame_dt;
 			if (keyboard_state[SDL_SCANCODE_UP])
-				text_buffer_scroll(&text_buffer, 0, -scroll_amount);
+				buffer_scroll(&text_buffer, 0, -scroll_amount_y);
 			if (keyboard_state[SDL_SCANCODE_DOWN])
-				text_buffer_scroll(&text_buffer, 0, +scroll_amount);
+				buffer_scroll(&text_buffer, 0, +scroll_amount_y);
 			if (keyboard_state[SDL_SCANCODE_LEFT])
-				text_buffer_scroll(&text_buffer, -scroll_amount, 0);
+				buffer_scroll(&text_buffer, -scroll_amount_x, 0);
 			if (keyboard_state[SDL_SCANCODE_RIGHT])
-				text_buffer_scroll(&text_buffer, +scroll_amount, 0);
+				buffer_scroll(&text_buffer, +scroll_amount_x, 0);
 		}
 			
 
@@ -151,14 +152,14 @@ int main(void) {
 
 		{
 			float x1 = 50, y1 = 50, x2 = window_widthf-50, y2 = window_heightf-50;
-			text_buffer_render(&text_buffer, x1, y1, x2, y2);
+			buffer_render(&text_buffer, x1, y1, x2, y2);
 			if (text_has_err()) {
 				printf("Text error: %s\n", text_get_err());
 				break;
 			}
 		}
 
-		//text_buffer_print_debug(&text_buffer);
+		//buffer_print_debug(&text_buffer);
 
 		SDL_GL_SwapWindow(window);
 	}
@@ -166,7 +167,7 @@ int main(void) {
 	SDL_GL_DeleteContext(glctx);
 	SDL_DestroyWindow(window);
 	SDL_Quit();
-	text_buffer_free(&text_buffer);
+	buffer_free(&text_buffer);
 	text_font_free(font);
 
 	return 0;
diff --git a/util.c b/util.c
index 6f252c6..c1446a8 100644
--- a/util.c
+++ b/util.c
@@ -3,11 +3,11 @@
 
 #include "base.h"
 
-static uint util_popcount(u64 x) {
+static u32 util_popcount(u64 x) {
 #ifdef __GNUC__
-	return (uint)__builtin_popcountll(x);
+	return (u32)__builtin_popcountll(x);
 #else
-	uint count = 0;
+	u32 count = 0;
 	while (x) {
 		x &= x-1;
 		++count;