add drawing

5 files changed, 77 insertions, 13 deletions

diff --git a/core.c b/core.c
index b72f104..04cab5a 100644
--- a/core.c
+++ b/core.c
@@ -36,10 +36,9 @@ static void add_scale(double amount) {
 	pos_y -= mouse_y / scale;
 }
 
-static uintptr_t current_addr() {
-	return to_addr(
-			pos_x + screen_width / 2 * scale,
-			pos_y + screen_width / 2 * scale);
+static void world_pos(double *x, double *y) {
+	*x = *x / scale + pos_x - 0.5;
+	*y = *y / scale + pos_y - 0.5;
 }
 
 static void goto_addr(uintptr_t addr) {
@@ -100,6 +99,11 @@ static void deinit_sdl() {
 	SDL_Quit();
 }
 
+static bool held(SDL_Keycode k) {
+	const uint8_t *state = SDL_GetKeyboardState(NULL);
+	return state[SDL_GetScancodeFromKey(k)];
+}
+
 static void handle_events() {
 	bool refresh = false;
 	SDL_Event e;
@@ -122,15 +126,33 @@ static void handle_events() {
 						break;
 				}
 				break;
-			case SDL_MOUSEMOTION:
-				if (e.motion.state & SDL_BUTTON_RMASK) {
+			case SDL_MOUSEMOTION:;
+				uint32_t state = e.motion.state;
+				if (state & SDL_BUTTON_MMASK ||
+						(state & SDL_BUTTON_RMASK && held(SDLK_LSHIFT))) {
 					pos_x -= (double) e.motion.xrel / scale;
 					pos_y -= (double) e.motion.yrel / scale;
 					refresh = true;
+				} else if (state & (SDL_BUTTON_LMASK | SDL_BUTTON_RMASK)) {
+					double x1 = e.motion.x - e.motion.xrel;
+					double y1 = e.motion.y - e.motion.yrel;
+					double x2 = e.motion.x; double y2 = e.motion.y;
+					world_pos(&x1, &y1); world_pos(&x2, &y2);
+					pencil(viewer,
+							x1, y1, x2, y2, !(state & SDL_BUTTON_RMASK));
+					refresh = true;
 				}
 				mouse_x = e.motion.x;
 				mouse_y = e.motion.y;
 				break;
+			case SDL_MOUSEBUTTONDOWN:;
+				double x = e.button.x; double y = e.button.y;
+				world_pos(&x, &y);
+				if (e.button.button == SDL_BUTTON_LEFT)
+					pencil(viewer, x, y, x, y, true);
+				else if (e.button.button == SDL_BUTTON_RIGHT)
+					pencil(viewer, x, y, x, y, false);
+				break;
 			case SDL_MOUSEWHEEL:
 				if (e.wheel.y == 0) break;
 				add_scale((double) e.wheel.y / 2);
diff --git a/memview.c b/memview.c
index 7f7dbd4..95a3c6c 100644
--- a/memview.c
+++ b/memview.c
@@ -39,7 +39,8 @@ uintptr_t to_addr(int x, int y) {
 	memcpy(&ux, &x, sizeof(unsigned int));
 	memcpy(&uy, &y, sizeof(unsigned int));
 	uintptr_t page = zorder(ux / PAGE_WIDTH, uy / PAGE_HEIGHT);
-	int offset = x % PAGE_WIDTH + y % PAGE_HEIGHT * PAGE_WIDTH;
+	int offset =
+		x % PAGE_WIDTH / CHAR_BIT + y % PAGE_HEIGHT * PAGE_WIDTH / CHAR_BIT;
 	return page * PAGE_SIZE + offset;
 }
 
@@ -135,3 +136,26 @@ bool render_pages(struct viewer *v,
 	}
 	return present;
 }
+
+static void write_bit(int fd, int x, int y, bool bit) {
+	uintptr_t addr = to_addr(x, y);
+	int bit_offs = x % CHAR_BIT;
+	uint8_t byte;
+	if (read_mem(fd, addr, &byte, 1) == -1) return;
+	byte = (byte & ~(1 << bit_offs)) | (bit << bit_offs);
+	write_mem(fd, addr, &byte, 1);
+}
+
+void pencil(struct viewer *v,
+		double x1, double y1, double x2, double y2, bool bit) {
+	double dx = (x2 - x1);
+	double dy = (y2 - y1);
+	int step = abs(dx) >= abs(dy) ? abs(dx) : abs(dy);
+	dx = dx / step; dy = dy / step;
+	double x = x1; double y = y1;
+	for (int i = 0; i <= step; i++) {
+		write_bit(v->fd, x, y, bit);
+		x = x + dx;
+		y = y + dy;
+	}
+}
diff --git a/memview.h b/memview.h
index 2a73ec4..47aab27 100644
--- a/memview.h
+++ b/memview.h
@@ -23,6 +23,7 @@ void destroy_viewer(struct viewer *v);
 
 bool render_pages(struct viewer *v,
 		int x, int y, int width, int height, double scale, bool refresh);
-void pencil(struct viewer *v, int x1, int y1, int x2, int y2, bool bit);
+void pencil(struct viewer *v,
+		double x1, double y1, double x2, double y2, bool bit);
 
 #endif
diff --git a/procfs.c b/procfs.c
index 2558f03..1e70274 100644
--- a/procfs.c
+++ b/procfs.c
@@ -75,14 +75,28 @@ err:
 	return -1;
 }
 
-int read_page(int fd, uintptr_t index, uint8_t *data) {
-	if (lseek(fd, index * PAGE_SIZE, SEEK_SET) == -1) 
-		return -1;
+int read_mem(int fd, uintptr_t addr, uint8_t *data, size_t size) {
+	if (lseek(fd, addr, SEEK_SET) == -1) return -1;
 	size_t n = 0;
-	while (n < PAGE_SIZE) {
-		ssize_t result = read(fd, data + n, PAGE_SIZE - n);
+	while (n < size) {
+		ssize_t result = read(fd, data + n, size - n);
 		if (result == -1) return -1;
 		n += result;
 	}
 	return 0;
 }
+
+int write_mem(int fd, uintptr_t addr, uint8_t *data, size_t size) {
+	if (lseek(fd, addr, SEEK_SET) == -1) return -1;
+	size_t n = 0;
+	while (n < size) {
+		ssize_t result = write(fd, data + n, size - n);
+		if (result == -1) return -1;
+		n += result;
+	}
+	return 0;
+}
+
+int read_page(int fd, uintptr_t index, uint8_t *data) {
+	return read_mem(fd, index * PAGE_SIZE, data, PAGE_SIZE);
+}
diff --git a/procfs.h b/procfs.h
index 28ef784..70a652e 100644
--- a/procfs.h
+++ b/procfs.h
@@ -11,6 +11,8 @@
 #endif
 
 int procfs_open(pid_t pid);
+int read_mem(int fd, uintptr_t addr, uint8_t *data, size_t size);
+int write_mem(int fd, uintptr_t addr, uint8_t *data, size_t size);
 int read_page(int fd, uintptr_t index, uint8_t *data);
 
 struct procfs_map {
@@ -20,5 +22,6 @@ struct procfs_map {
 };
 
 ssize_t procfs_maps(pid_t pid, struct procfs_map **maps);
+char procfs_state(pid_t pid);
 
 #endif