feat: add bounding box calculation

src/application/applicationstate.c

@@ -81,7 +81,8 @@ begin_click_dispatch:
                               .stroke_width = 0.01};
             VektorShape shape = (VektorShape){
                 .primitive = linePrimitive, .z_index = 0, .style = style};
-            vektor_shapebuffer_add_shape(state->shapeBuffer, shape);
+            vektor_shapebuffer_add_shape(state->shapeBuffer, vektor_shape_new(linePrimitive, style, 0));
+
 
             state->selectedShape =
                 &(state->shapeBuffer->shapes[state->shapeBuffer->count - 1]);
@@ -96,6 +97,13 @@ begin_click_dispatch:
 
         vektor_polyline_add_point(state->selectedShape->primitive.polyline,
                                   pos);
+
+                                              vektor_shapes_update_bbox(state->shapeBuffer);
+
+
+                    for (size_t i = 0; i < state->shapeBuffer->count; i++) {
+                g_print("<%f,%f>-<%f,%f>\n", state->shapeBuffer->shapes[i].bbox.min.x, state->shapeBuffer->shapes[i].bbox.min.y, state->shapeBuffer->shapes[i].bbox.max.x, state->shapeBuffer->shapes[i].bbox.max.y);
+            }
     }
 }
 
@@ -111,6 +119,7 @@ void vektor_appstate_new(VektorWidgetState* wstate, VektorAppState* stateOut) {
     stateOut->canvas = malloc(sizeof(VektorCanvas));
     stateOut->widgetState = wstate;
     stateOut->currentColor = vektor_color_blank;
+    stateOut->selectedShape = NULL;
     vektor_canvas_init(wstate, stateOut->canvas, stateOut->shapeBuffer);
 
     // link all the buttons

src/core/primitives.c

@@ -1,4 +1,7 @@
 #include "primitives.h"
+#include <assert.h>
+#include <math.h>
+#include <stddef.h>
 
 VektorPolyline* vektor_polyline_new(void) {
     VektorPolyline* pl = malloc(sizeof(VektorPolyline));
@@ -55,3 +58,56 @@ void vektor_shapebuffer_add_shape(VektorShapeBuffer* buffer,
     }
     buffer->shapes[buffer->count++] = shape;
 }
+
+VektorBBox polyline_mk_bbox(VektorPrimitive prim) {
+    float min_x, max_x, min_y, max_y;
+    for (size_t i = 0; i < prim.polyline->count; i++) {
+        V2 p = prim.polyline->points[i];
+        min_x = fminf(min_x, p.x);
+        min_y = fminf(min_y, p.y);
+
+        max_x = fminf(max_x, p.x);
+        max_y = fminf(max_y, p.y);
+    }
+    return (VektorBBox){(V2){min_x, min_y}, (V2){max_x, max_y}};
+}
+
+VektorBBox polygon_mk_bbox(VektorPrimitive prim) {
+    float min_x, max_x, min_y, max_y;
+    for (size_t i = 0; i < prim.polygon->count; i++) {
+        V2 p = prim.polygon->points[i];
+        min_x = fminf(min_x, p.x);
+        min_y = fminf(min_y, p.y);
+
+        max_x = fminf(max_x, p.x);
+        max_y = fminf(max_y, p.y);
+    }
+    return (VektorBBox){(V2){min_x, min_y}, (V2){max_x, max_y}};
+}
+
+VektorBBox vektor_mk_bbox(VektorPrimitive prim) {
+    switch (prim.kind) {
+    case VEKTOR_POLYLINE:
+        return polyline_mk_bbox(prim);
+        break;
+
+    case VEKTOR_POLYGON:
+        return polygon_mk_bbox(prim);
+        break;
+
+    default:
+        // TODO: fill in all primitives
+        break;
+    }
+}
+
+VektorShape vektor_shape_new(VektorPrimitive prim, VektorStyle style,
+                             int z_index) {
+    return (VektorShape){.primitive = prim, .style = style, .z_index = z_index, .bbox=vektor_mk_bbox(prim)};
+}
+
+void vektor_shapes_update_bbox(VektorShapeBuffer* buffer) {
+    for (size_t i = 0; i < buffer->count; i++) {
+        buffer->shapes[i].bbox = vektor_mk_bbox(buffer->shapes[i].primitive);
+    }
+}

src/core/primitives.h

@@ -51,12 +51,26 @@ typedef struct {
     float stroke_width;
 } VektorStyle;
 
+typedef struct {
+    V2 min;
+    V2 max;
+} VektorBBox;
+
 typedef struct {
     VektorStyle style;
     int z_index;
+    VektorBBox bbox;
     VektorPrimitive primitive;
 } VektorShape;
 
+VektorBBox polyline_mk_bbox(VektorPrimitive prim);
+VektorBBox polygon_mk_bbox(VektorPrimitive prim);
+
+VektorBBox vektor_mk_bbox(VektorPrimitive prim);
+
+VektorShape vektor_shape_new(VektorPrimitive prim, VektorStyle style,
+                             int z_index);
+
 typedef struct {
     VektorShape* shapes;
     size_t count;
@@ -64,5 +78,5 @@ typedef struct {
 } VektorShapeBuffer;
 
 void vektor_shapebuffer_add_shape(VektorShapeBuffer* buffer, VektorShape shape);
-
+void vektor_shapes_update_bbox(VektorShapeBuffer* buffer);
 #endif // PRIMITIVES_H_