add option for discarding partial frames

src/components/Player.vue

@@ -32,6 +32,10 @@
         </label>
         <input type="checkbox" v-model="sortDirection" id="sortDirection">
       </div>
+      <div>
+        <label for="discard">Discard partial frames</label>
+        <input type="checkbox" v-model="discardPartial" id="discard">
+      </div>
     </div>
   </div>
 </template>
@@ -55,6 +59,7 @@ export default {
       fullscreen: false,
       sortBySize: false,
       sortDirection: false,
+      discardPartial: false,
       position: 0,
       tmp_ctx: null,
       animation_id: null,
@@ -68,7 +73,8 @@ export default {
   computed: {
     frames: function () {
       if (this.image === null) return 0;
-      return Math.ceil((this.image.width - this.offset[0]) / this.width) * Math.ceil((this.image.height - this.offset[1]) / this.height);
+      const roundFn = this.discardPartial ? Math.floor : Math.ceil;
+      return roundFn((this.image.width - this.offset[0]) / this.width) * roundFn((this.image.height - this.offset[1]) / this.height);
     },
     canvas_height: function () {
       return this.height * this.zoom;
@@ -81,7 +87,7 @@ export default {
 
       let sequence = [];
       for (let pos = 0; pos < this.frames; pos++) {
-        let wb = Math.ceil((this.image.width - this.offset[0]) / this.width); // width_blocks
+        let wb = (this.discardPartial ? Math.floor : Math.ceil)((this.image.width - this.offset[0]) / this.width); // width_blocks
         let x = this.offset[0] + (pos % wb) * this.width; // x offset
         let w = x + this.width < this.image.width ? this.width : this.image.width - x; // frame width
         let y = this.offset[1] + Math.floor(pos / wb) * this.height; // y offset