Zoom / Magnify + MouseWheel about canvas HOT 5 CLOSED

Hi!

Such a function would make sense, since the HTML canvas also lets you define both an internal size and a display size, which this package is missing. I'll have to think about where to put that. I would not recommend this for zooming though, since it would mean that the image would be rendered at a huge or tiny resolution internally and then scaled to the window size.

Instead of using PutImageData, you could also use DrawImage:
cv.DrawImage("u2_"+t.Type+".pcx", float64(t.X), float64(t.Y))

This will load the pcx file (which can be decoded after importing the pcx package), and the canvas library will cache the image. Or you can use the explicit canvas.LoadImage function.

I like the MouseWheel callback btw, will add that.

from canvas.

Could you use: https://godoc.org/github.com/veandco/go-sdl2/gfx#ZoomSurface

from canvas.

https://github.com/5k3105/tilemap4

λ .\tilemap4.exe
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x100 pc=0x4d9e22]

goroutine 1 [running, locked to thread]:
github.com/tfriedel6/canvas.loadImageRGBA(0xc042050100, 0x4b49ce, 0xc042058340, 0x0)
        C:/Users/clott/go/src/github.com/tfriedel6/canvas/images.go:107 +0xd2
github.com/tfriedel6/canvas.LoadImage(0x5a2620, 0xc042050100, 0x5e1f40, 0xc042050100, 0x0)
        C:/Users/clott/go/src/github.com/tfriedel6/canvas/images.go:31 +0x574
main.init.0()
        C:/Users/clott/go/src/github.com/5k3105/tilemap4/main.go:41 +0x2ac

DrawImage does work, but if I try to LoadImage with the decoded image I get the above error. If I try to LoadImage with the filename I get:
failed to load image: Unsupported source type

In both instances I do have the pcx library imported.

from canvas.

Ah, I see what the problem is there. LoadImage has to be called after the window is created, otherwise the GL context is not set yet and you get the above error.

Calling LoadImage with the filename should work though (also only after CreateWindow). Can you show the code where that fails?

from canvas.

I've updated to load file after sdlcanvas.CreateWindow : https://github.com/5k3105/tilemap4

The reason why I got failed to load image: Unsupported source type was I passed a file handle instead of the file string. My mistake :D

Zoom works mostly. I need to check why the mouse cursor does not track correctly.

Thanks!

from canvas.