I have a map that is too big to load into a bitmap. It is 3361 * 4496 pixels. Not all of it loads.
I have a Rect that holds the map and as you scroll around the screen, by changing the origin the map scrolls in the imageview.
I’m sure there is a better way of doing this. But I have cut the map into 42 overlapping map sections, most of them 900*1200 pixels and I load the first one in the top left corner.
When I move scroll over the screen the map follows my finger and when it reaches a certain threshold (for when I’m going east, this is at -1277) the existing map is ditched and the next one to the east is loaded. The position of the Rect is then changed to show the same part of the map that was showing on the discarded map.
It all kind of works, with a short delay during scrolling as the new map is loaded. The transistions don’t match up exactly, but that’s a bit more investigation.
My question is, is there a better way of doing this?
I have a Rect that holds the map and as you scroll around the screen, by changing the origin the map scrolls in the imageview.
I’m sure there is a better way of doing this. But I have cut the map into 42 overlapping map sections, most of them 900*1200 pixels and I load the first one in the top left corner.
When I move scroll over the screen the map follows my finger and when it reaches a certain threshold (for when I’m going east, this is at -1277) the existing map is ditched and the next one to the east is loaded. The position of the Rect is then changed to show the same part of the map that was showing on the discarded map.
It all kind of works, with a short delay during scrolling as the new map is loaded. The transistions don’t match up exactly, but that’s a bit more investigation.
My question is, is there a better way of doing this?
B4X:
Sub Class_Globals
Private Root As B4XView 'ignore
Private xui As XUI 'ignore
Private ImageView1 As ImageView
Private Panel1 As Panel
Dim start_x, start_y As Float
Dim ii_image_top_y, ii_image_left_x As Int
Private Label1 As Label
Type maprecord(map_offset As Int, section_name As String, northmap As Int, eastmap As Int, southmap As Int, westmap As Int, pixelwidth As Int, pixelheight As Int)
Private mapTable(42) As maprecord
Private ii_current_map_offset As Int
End Sub
'You can see the list of page related events in the B4XPagesManager object. The event name is B4XPage.
Sub f_add_Bike_map_section(map_offset As Int, section_name As String, northmap As Int, eastmap As Int, southmap As Int, westmap As Int, pixelwidth As Int, pixelheight As Int)
mapTable(map_offset).section_name=section_name
mapTable(map_offset).northmap=northmap
mapTable(map_offset).eastmap=eastmap
mapTable(map_offset).southmap=southmap
mapTable(map_offset).westmap=westmap
mapTable(map_offset).pixelwidth=pixelwidth
mapTable(map_offset).pixelheight=pixelheight
End Sub
Sub f_populate_map_sections
f_add_Bike_map_section(0,"bike_section_0x0.jpg",-1,6,1,-1,1348,2616)
f_add_Bike_map_section(1,"bike_section_0x1.jpg",0,7,2,-1,1348,2616)
f_add_Bike_map_section(2,"bike_section_0x2.jpg",1,8,3,-1,1348,2616)
f_add_Bike_map_section(3,"bike_section_0x3.jpg",2,9,4,-1,1348,2616)
f_add_Bike_map_section(4,"bike_section_0x4.jpg",3,10,5,-1,1348,2616)
f_add_Bike_map_section(5,"bike_section_0x5.jpg",4,11,-1,-1,1348,2616)
f_add_Bike_map_section(6,"bike_section_1x0.jpg",-1,12,7,0,1348,2616)
f_add_Bike_map_section(7,"bike_section_1x1.jpg",6,13,8,1,1348,2616)
f_add_Bike_map_section(8,"bike_section_1x2.jpg",7,14,9,2,1348,2616)
f_add_Bike_map_section(9,"bike_section_1x3.jpg",8,15,10,3,1348,2616)
f_add_Bike_map_section(10,"bike_section_1x4.jpg",9,16,11,4,1348,2616)
f_add_Bike_map_section(11,"bike_section_1x5.jpg",10,17,-1,5,1348,2616)
f_add_Bike_map_section(12,"bike_section_2x0.jpg",-1,18,13,6,1348,2616)
f_add_Bike_map_section(13,"bike_section_2x1.jpg",12,19,14,7,1348,2616)
f_add_Bike_map_section(14,"bike_section_2x2.jpg",13,20,15,8,1348,2616)
f_add_Bike_map_section(15,"bike_section_2x3.jpg",14,21,16,9,1348,2616)
f_add_Bike_map_section(16,"bike_section_2x4.jpg",15,22,17,10,1348,2616)
f_add_Bike_map_section(17,"bike_section_2x5.jpg",16,23,-1,11,1348,2616)
f_add_Bike_map_section(18,"bike_section_3x0.jpg",-1,24,19,12,1348,2616)
f_add_Bike_map_section(19,"bike_section_3x1.jpg",18,25,20,13,1348,2616)
f_add_Bike_map_section(20,"bike_section_3x2.jpg",19,26,21,14,1348,2616)
f_add_Bike_map_section(21,"bike_section_3x3.jpg",20,27,22,15,1348,2616)
f_add_Bike_map_section(22,"bike_section_3x4.jpg",21,28,23,16,1348,2616)
f_add_Bike_map_section(23,"bike_section_3x5.jpg",22,29,-1,17,1348,2616)
f_add_Bike_map_section(24,"bike_section_4x0.jpg",-1,30,25,18,1348,2616)
f_add_Bike_map_section(25,"bike_section_4x1.jpg",24,31,26,19,1348,2616)
f_add_Bike_map_section(26,"bike_section_4x2.jpg",25,32,27,20,1348,2616)
f_add_Bike_map_section(27,"bike_section_4x3.jpg",26,33,28,21,1348,2616)
f_add_Bike_map_section(28,"bike_section_4x4.jpg",27,34,29,22,1348,2616)
f_add_Bike_map_section(29,"bike_section_4x5.jpg",28,35,-1,23,1348,2616)
f_add_Bike_map_section(30,"bike_section_5x0.jpg",-1,36,31,24,1348,2616)
f_add_Bike_map_section(31,"bike_section_5x1.jpg",30,37,32,25,1348,2616)
f_add_Bike_map_section(32,"bike_section_5x2.jpg",31,38,33,26,1348,2616)
f_add_Bike_map_section(33,"bike_section_5x3.jpg",32,39,34,27,1348,2616)
f_add_Bike_map_section(34,"bike_section_5x4.jpg",33,40,35,28,1348,2616)
f_add_Bike_map_section(35,"bike_section_5x5.jpg",34,41,-1,29,1348,2616)
f_add_Bike_map_section(36,"bike_section_6x0.jpg",-1,-1,37,30,1348,2616)
f_add_Bike_map_section(37,"bike_section_6x1.jpg",36,-1,38,31,1348,2616)
f_add_Bike_map_section(38,"bike_section_6x2.jpg",37,-1,39,32,1348,2616)
f_add_Bike_map_section(39,"bike_section_6x3.jpg",38,-1,40,33,1348,2616)
f_add_Bike_map_section(40,"bike_section_6x4.jpg",39,-1,41,34,1348,2616)
f_add_Bike_map_section(41,"bike_section_6x5.jpg",40,-1,-1,35,1348,2616)
End Sub
Public Sub Initialize
' B4XPages.GetManager.LogEvents = True
End Sub
'This event will be called once, before the page becomes visible.
Sub f_draw_an_image_page
Dim Canvas1 As Canvas
Canvas1.Initialize(ImageView1)
Dim Bitmap1 As Bitmap
Bitmap1.Initialize(File.DirAssets, mapTable(ii_current_map_offset).section_name)
Dim DestRect As Rect
Try
DestRect.Initialize(0, 0, 900dip , 1200dip )
Catch
Log("Whoops!")
End Try
Canvas1.DrawBitmap(Bitmap1, Null, DestRect) 'draws the bitmap to the destination rectangle.
End Sub
Private Sub B4XPage_Created (Root1 As B4XView)
Root = Root1
Root.LoadLayout("b4xBikeMap")
f_populate_map_sections
f_draw_an_image_page
B4XPages.SetTitle(Me, "Bike Map")
ii_current_map_offset=0
End Sub
'You can see the list of page related events in the B4XPagesManager object. The event name is B4XPage.
Sub move_Image(ax As Int, ay As Int)
' To go North ay is negative
' To go South ay is positive
' To go West ax is Positive
' To go East ax is negative
If ax>0 And mapTable(ii_current_map_offset).westmap<>-1 Then
ii_current_map_offset=mapTable(ii_current_map_offset).westmap
ax=0
f_draw_an_image_page
ii_image_left_x=ii_image_left_x - 1178
else if ay>0 And mapTable(ii_current_map_offset).northmap<>-1 Then
ii_current_map_offset=mapTable(ii_current_map_offset).Northmap
ay=0
f_draw_an_image_page
ii_image_top_y=ii_image_top_y - 1027
else if ax<-1277 And mapTable(ii_current_map_offset).eastmap<>-1 Then
ii_current_map_offset=mapTable(ii_current_map_offset).eastmap
ax=0
f_draw_an_image_page
ii_image_left_x=ii_image_left_x + 1178
else if ay<-1127 And mapTable(ii_current_map_offset).southmap<>-1 Then
ii_current_map_offset=mapTable(ii_current_map_offset).southmap
ay=0
f_draw_an_image_page
ii_image_top_y=ii_image_top_y + 1227
End If
If ay>0 Then
ay=0
End If
If ax>0 Then
ax=0
End If
ImageView1.Top= ay
ImageView1.left= ax
Label1.Text=ax & " " & ay & " " & ii_image_left_x & " " & ii_image_top_y
End Sub
'
Private Sub Panel1_Touch (Action As Int, X As Float, Y As Float)
Select Action
Case 0
ii_image_top_y=ImageView1.Top
ii_image_left_x=ImageView1.left
start_x=Round(X)
start_y=Round(Y)
Case 1
move_Image(X - start_x +ii_image_left_x,Y - start_y + ii_image_top_y)
Case 2
move_Image(X - start_x +ii_image_left_x,Y - start_y + ii_image_top_y)
End Select
End Sub
